GTA
All Springer/NP/PCP Air Gun Discussion General => Air Gun Gate => Topic started by: Underdog on February 08, 2016, 05:09:42 PM
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When I first got into airguns, one of the first things I read was over on CharlieDaTuna's website about using pellets no larger than about 8 grains because it can damage your spring.
Is this true?
I've just ordered a HW95 from AoA, with a box of 10.65 grain Baracuda Match H&N pellets. Maybe I should have stayed below 8 grains?
What do you think?
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Not according to my experience....
I've used .22 25.9gr JSB Monsters in my standard Diana 34 without problems and even did shot very accurate as well !
I think it is a myth pending around on forums.
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Use the pellets that gives you best accuracy.
A spring is easy to replace and not very expensive.
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If a pellet is to heavy for the spring the piston can rebound which is something you want to avoid, to light a pellet is also not good, less cushioning effect on the piston.
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Before I put a soft tune in my D34 I was shooting JSB 10gr. through her and it was very accurate. When I shot lighter pellets it was still accurate but it was not as smooth and my gun would have a little ring at the end of the shot. IMO if your gun shoots great, sounds like everything is working like it should then I would shoot that ammo. Remember, Springs and seals are considered consumables.
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Yes. A too heavy of a pellet may get stuck in the barrel and never make it out.
On the other hand, if your gun spits the pellets accurately, then they are obviously not too heavy. Also, I think heavier pellets cannot damage your gun components while too light of a pellet does. Just think of the mechanics of a springer air gun..
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Can pellets be too heavy for a particular springer?
YES!
Can pellets be too light for a particular springer?
YES!
Can this damage the springer?
YES!
How long do you want YOUR springer and/or scope to last and shoot accurately?
YOUR CHOICE!
-
Can pellets be too heavy for a particular springer?
YES!
Can pellets be too light for a particular springer?
YES!
Can this damage the springer?
YES!
How long do you want YOUR springer and/or scope to last and shoot accurately?
YOUR CHOICE!
Ummmm....
That's not actually helpful. Obviously I'd like to make a choice that doesn't damage my new rifle! I mean, who would choose to damage their brand new (insert toy of choice here)?!!
But you don't tell me how to tell if a pellet is too light or too heavy....
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If you have a to lite of pellet? You'll feel a slam when you fire it.
To heavy? You'll feel the double rebound effect.
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If you don't go to extremes and stay between 7 and 11 grains, you'll be fine.
If your Barracudas are accurate, use those.
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Ok. Thanks! I'll just have to try it out to see what effect certain pellets have then. Either a rebound or a slam.
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The way I judge it is by pellet drop. If you get a pellet that is hitting lower than the average I consider it too heavy. Why shoot the heavies when there are plenty other pellets that stay within the allowed zero....
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When I first got into airguns, one of the first things I read was over on CharlieDaTuna's website about using pellets no larger than about 8 grains because it can damage your spring.
Is this true?
I've just ordered a HW95 from AoA, with a box of 10.65 grain Baracuda Match H&N pellets. Maybe I should have stayed below 8 grains?
What do you think?
Jim;
Damage is a relative term.
All things have lives. Springs included.
Back in the days when people thought that springs had to last a generation (or more), to have to replace a broken spring after 7,000 rounds was considered "damage".
In this current day and age of printer cartridges and toners, we have become accustomed to the idea of things having finite lives.
A very heavy pellet will make the piston rebound, yes, but that is not the problem. The problem is that in rebounding, the piston compresses the spring, which then distends again. Extreme cases can do this three times per shot. At three cycles per shot, fatigue sets into the steel much faster than when you use the spring one cycle per shot.
So, when a spring dies after 2,500 rounds of heavy pellet usage, people say your spring got "damaged".
Too light a pellet and what suffers are your seals. The seals take the brunt of decelerating the piston at the end of its travel, and that energy has to go somewhere. USUALLY, it goes to destroy the seals.
One aspect about springers that few people realize is that a well adjusted springer will always give you peak Muzzle Energy with the best pellet for the power plant.
Some power plants are highly strung instead of being finely tuned and this makes them pellet finicky. Some power plants look for maximum muzzle velocity and then disregard the effect of excessive MV in a pellet's ballistics. BUT, for some shooters, the ONLY solution to taming down the beast is using a heavy pellet. The heavy pellet will give you lower velocity and, sometimes that improves the accuracy.
As you gain experience, you will learn to LISTEN to your rifle. The sounds (and even better, the LACK thereof), usually can tell you a lot of how your gun is performing and if you can improve it.
A few heavy pellets will not hurt any quality spring, so test to your heart's content. When you find a pellet that the gun likes, is when the fun starts.
IN GENERAL, small compression chambers with smallish pistons (like the HW's and the AA's) work their best with pellets in the region of 8 to 9 grains in 0.177" cal. but all rifles are a law unto their own, so test. Test everything, from 7.33's to 10.5's
Also check to see if your particular barrel likes the pellets lubed (and with what) or not.
HTH and keep us posted.
Hector Medina
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Great info here. I'm a total newb when it comes to springers (airguns in general, actually), so all of this is great!
Thanks again!
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What is the displacement of a typical springer cylinder-
stroke
diameter
Off top of your heads-?
preloaded length of typical springer spring? unpreloaded length
Thanks
Charlie
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Excellent info Hector, thanks for that.
I just saw this thread and can't add a whole lot but wanted to chime in.
For the best performance, you need to use the correct pellet weight for the specific airgun power plant, as Hector says. Not all airguns are equipped the same, especially springers. There are different chamber sizes and main spring diameters, number of coils and thickness of wire used. All contributing to generating a different amount of air volume and force behind it. So, you need to pick the pellet that gives the best performance with the specific power plant of the airgun. We "generally" put our airguns in classes of power such as low, medium, high and magnum just as a rough way to determine the correct ammo. It gets you in the ballpark as to what weight pellet to look at or what to not look at. You would not use PBA in a magnum class airgun. Nor use a heavy weight round in a lower powered airgun. Sticking with the correct weight pellet will not only give a better performance but will help lengthen the time between maintenance intervals and spring replacement, IMHO.
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Is spring rebound, with too heavy of a pellet, a theoretical beast or is it factual?
I just cannot see how to heavy of a pellet can rebound the spring, and if it actually could do so, how it could rebound it more than once. It's rather easy to test this by blocking off the compression chamber hole and shooting the spring, and this would be the WORST case scenario (heaviest pellet in the world). I can see the spring maybe rebound once slightly under these extreme (non-real world) circumstances, but i think it would be a rather shor rebound to the tune of 1/4-1/2" at most.
In any other scenario where the pellet actually can move even a little bit under spring pressure, it would not cause any rebound, at least not in my head and using my logic, so again i ask, has this rebound theory been tested and proven or does it only remain theoretical?
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I like Hectors reply. In my experience, listening to your springer as it fires tells you a lot. I have settled on JSB/AA 8.4 gr for my RWS 34. If I use 7.3 gr JSB/AA pellets, I hear a ring at the end of the shot cycle (piston hitting the cylinder). If I shoot AA/JSB 10.3 gr, I hear more buzz (spring bounce). In either case (7.3 and 10.3 gr), the accuracy is not quite as good as the accuracy I get with the 8.4 gr pellet.
I also find that how tightly the pellet fits into the breach also is a factor: I can shoot Crosman 7.4 gr premiers and not get a ring in the gun, and get decent groups. The problem with shooting these tight pellets is getting consistent seating in the breach (which can be a bit of a hassle, even with a pellet seating tool). Since the JSB/AA 8.4 gr pellets seat nicely and consistently in the breach, I shoot them all the time.
Hope you find your best pellet. Straight shooting!
-
Can pellets be too heavy for a particular springer?
YES!
Can pellets be too light for a particular springer?
YES!
Can this damage the springer?
YES!
How long do you want YOUR springer and/or scope to last and shoot accurately?
YOUR CHOICE!
If I read this answer I'm almost afraid to even use my springer at all LOL
I go for Benjihunter's answer: Use the pellets that gives you best accuracy.
And the Baracuda's are fine...
-
Can pellets be too heavy for a particular springer?
YES!
Can pellets be too light for a particular springer?
YES!
Can this damage the springer?
YES!
How long do you want YOUR springer and/or scope to last and shoot accurately?
YOUR CHOICE!
If I read this answer I'm almost afraid to even use my springer at all LOL
I go for Benjihunter's answer: Use the pellets that gives you best accuracy.
And the Baracuda's are fine...
Actually, this post was made AFTER some discussion of the subject, in this thread, where the possible benefit vs damage had been noted.
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I think it is a myth pending around on forums.
This has been my opinion also for years now.
I have a little Gamo .177 and was told not to shoot the 10.5gr pellets because it would damage it,.....well, been shooting the 10.5gr pellets for 9 years now and the guns still going strong :) :)
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I spoke to a fellow GTA member that lives near me, and he has the Beeman R9 (basically the same as the HW95). He tells me he uses the H&N Field Target Trophy pellets at 8.64 grains. So I added those to my order today...
We'll see how it all works out. I've got several others that I bought at Wally World, and I'll do a comparison shoot when I get the new toy.
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When I first got into airguns, one of the first things I read was over on CharlieDaTuna's website about using pellets no larger than about 8 grains because it can damage your spring.
Is this true?
I've just ordered a HW95 from AoA, with a box of 10.65 grain Baracuda Match H&N pellets. Maybe I should have stayed below 8 grains?
What do you think?
One aspect about springers that few people realize is that a well adjusted springer will always give you peak Muzzle Energy with the best pellet for the power plant.
Hector Medina
Always enjoy your posts, especially when you agree with me. ;)
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I don't have a chrony, so I use accuracy and penetration to decide what pellets are best for a certain airgun. I find that wood targets don't work well for penetration tests as often there's not enough variation to give me any useful feedback.
I prefer steel cans. Coffee cans, soup cans, empty aresol cans, whatever.
What I'm looking for is double penetration, through the front and out the back. And something of a larger hole out the backside.
I'll keep shooting at a farther distance until one of the pellets does not make it through both sides, and then I'll know that pellet is not as efficient in that gun.
I've got to order 2 or 3 different tins of 5mm pellets. I think I'll look for something long and pointy, and not overly heavy for this caliber.
-
Can pellets be too heavy for a particular springer?
YES!
Can pellets be too light for a particular springer?
YES!
Can this damage the springer?
YES!
How long do you want YOUR springer and/or scope to last and shoot accurately?
YOUR CHOICE!
If I read this answer I'm almost afraid to even use my springer at all LOL
I go for Benjihunter's answer: Use the pellets that gives you best accuracy.
And the Baracuda's are fine...
LOL!!! I'm laughing because my eldest brother, who got me on this slippery slope, recently chastised me for all the shooting I do in my basement with my air guns. He said "You're going to wear out your guns if you keep shooting them like that." I looked him straight in the eye and said, "I want to be known as the guy who wore out his air rifle!"
I got into this hobby to SHOOT, not to have bunch of guns to look at in their racks. If I destroy a spring here or a seal there, that's the opportunity I look forward to in order to learn how to replace the worn out parts.
FWIW, my Benji's like heavier pellets...they seem to group better, and have more retained energy at distance for the units I hunt with. The dead squirrels attest to that. Look at Chairgun Pro and run your numbers is you're going to hunt your gun. Energy at distance is important for humane kills.
I can hardly wait until I break/wear out my very first air gun. LMBO!!!
It's all about having fun, and I'm having a blast. I respect the input from the seasoned veterans here, but I guess this old guy is just concerned with having a good time and learning something new every day. YMMV.
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When I first got into airguns, one of the first things I read was over on CharlieDaTuna's website about using pellets no larger than about 8 grains because it can damage your spring.
Is this true?
I've just ordered a HW95 from AoA, with a box of 10.65 grain Baracuda Match H&N pellets. Maybe I should have stayed below 8 grains?
What do you think?
Jim;
Damage is a relative term.
All things have lives. Springs included.
Back in the days when people thought that springs had to last a generation (or more), to have to replace a broken spring after 7,000 rounds was considered "damage".
In this current day and age of printer cartridges and toners, we have become accustomed to the idea of things having finite lives.
A very heavy pellet will make the piston rebound, yes, but that is not the problem. The problem is that in rebounding, the piston compresses the spring, which then distends again. Extreme cases can do this three times per shot. At three cycles per shot, fatigue sets into the steel much faster than when you use the spring one cycle per shot.
So, when a spring dies after 2,500 rounds of heavy pellet usage, people say your spring got "damaged".
Too light a pellet and what suffers are your seals. The seals take the brunt of decelerating the piston at the end of its travel, and that energy has to go somewhere. USUALLY, it goes to destroy the seals.
One aspect about springers that few people realize is that a well adjusted springer will always give you peak Muzzle Energy with the best pellet for the power plant.
Some power plants are highly strung instead of being finely tuned and this makes them pellet finicky. Some power plants look for maximum muzzle velocity and then disregard the effect of excessive MV in a pellet's ballistics. BUT, for some shooters, the ONLY solution to taming down the beast is using a heavy pellet. The heavy pellet will give you lower velocity and, sometimes that improves the accuracy.
As you gain experience, you will learn to LISTEN to your rifle. The sounds (and even better, the LACK thereof), usually can tell you a lot of how your gun is performing and if you can improve it.
A few heavy pellets will not hurt any quality spring, so test to your heart's content. When you find a pellet that the gun likes, is when the fun starts.
IN GENERAL, small compression chambers with smallish pistons (like the HW's and the AA's) work their best with pellets in the region of 8 to 9 grains in 0.177" cal. but all rifles are a law unto their own, so test. Test everything, from 7.33's to 10.5's
Also check to see if your particular barrel likes the pellets lubed (and with what) or not.
HTH and keep us posted.
Hector Medina
Well said. It merits a re-read.
.
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What is the displacement of a typical springer cylinder-
stroke
diameter
Off top of your heads-?
preloaded length of typical springer spring? unpreloaded length
Thanks
Charlie
Phoebeisis:
Lots of good info in this forum, you just need to search:
http://www.gatewaytoairguns.org/GTA/index.php?topic=28816.msg263806#msg263806 (http://www.gatewaytoairguns.org/GTA/index.php?topic=28816.msg263806#msg263806)
;-)
We should thank Dave for those lists.
Keep well and shoot straight!
Hector Medina
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Is spring rebound, with too heavy of a pellet, a theoretical beast or is it factual?
I just cannot see how to heavy of a pellet can rebound the spring, and if it actually could do so, how it could rebound it more than once. It's rather easy to test this by blocking off the compression chamber hole and shooting the spring, and this would be the WORST case scenario (heaviest pellet in the world). I can see the spring maybe rebound once slightly under these extreme (non-real world) circumstances, but i think it would be a rather shor rebound to the tune of 1/4-1/2" at most.
In any other scenario where the pellet actually can move even a little bit under spring pressure, it would not cause any rebound, at least not in my head and using my logic, so again i ask, has this rebound theory been tested and proven or does it only remain theoretical?
STIJA:
It all depends on who and what you are willing to believe.
SOME rifles have APPRECIABLE piston rebound under certain conditions, like the Walther LGU when the TopHat is a loose fit inside the piston. Others you appreciate the rebound in the way the efficiency of the system is affected by very heavy pellets. In others you can actually SEE the rebound when the shot cycle is filmed in high speed video.
If you are handy with Maths and Differential Equations, I would suggest you read Domingo Tavella's paper about Internal Ballistics of the Spring Piston Airgun:
https://www.researchgate.net/publication/274638905_Internal_Ballistics_of_Spring_Piston_Airguns (https://www.researchgate.net/publication/274638905_Internal_Ballistics_of_Spring_Piston_Airguns)
Some of the equations are a little complicated, but read the text and try to understand the discretization process that gets you a mathematical model that yields not only lots of information, but also great insights on where the guns can be improved.
If you don't want to believe the serious people that write about this, or the maths involved, then I guess that for you it will always stay in the realm of theory.
JMHO
HM
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I like Hectors reply. In my experience, listening to your springer as it fires tells you a lot. I have settled on JSB/AA 8.4 gr for my RWS 34. If I use 7.3 gr JSB/AA pellets, I hear a ring at the end of the shot cycle (piston hitting the cylinder). If I shoot AA/JSB 10.3 gr, I hear more buzz (spring bounce). In either case (7.3 and 10.3 gr), the accuracy is not quite as good as the accuracy I get with the 8.4 gr pellet.
I also find that how tightly the pellet fits into the breach also is a factor: I can shoot Crosman 7.4 gr premiers and not get a ring in the gun, and get decent groups. The problem with shooting these tight pellets is getting consistent seating in the breach (which can be a bit of a hassle, even with a pellet seating tool). Since the JSB/AA 8.4 gr pellets seat nicely and consistently in the breach, I shoot them all the time.
Hope you find your best pellet. Straight shooting!
Fred;
The real difference between the Crosman Premiers and the JSB Exacts is WHERE they seal.
CP's seal at the HEAD, JSB's seal at the SKIRT. The insertion effort for the CP's is perceived as higher because you do that effort, for the JSB's the gun does most of the effort.
;-)
HM
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Always enjoy your posts, especially when you agree with me. ;)
You have just put my heart at ease.
;-)
Héctor
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Is spring rebound, with too heavy of a pellet, a theoretical beast or is it factual?
I just cannot see how to heavy of a pellet can rebound the spring, and if it actually could do so, how it could rebound it more than once. It's rather easy to test this by blocking off the compression chamber hole and shooting the spring, and this would be the WORST case scenario (heaviest pellet in the world). I can see the spring maybe rebound once slightly under these extreme (non-real world) circumstances, but i think it would be a rather shor rebound to the tune of 1/4-1/2" at most.
In any other scenario where the pellet actually can move even a little bit under spring pressure, it would not cause any rebound, at least not in my head and using my logic, so again i ask, has this rebound theory been tested and proven or does it only remain theoretical?
STIJA:
It all depends on who and what you are willing to believe.
SOME rifles have APPRECIABLE piston rebound under certain conditions, like the Walther LGU when the TopHat is a loose fit inside the piston. Others you appreciate the rebound in the way the efficiency of the system is affected by very heavy pellets. In others you can actually SEE the rebound when the shot cycle is filmed in high speed video.
If you are handy with Maths and Differential Equations, I would suggest you read Domingo Tavella's paper about Internal Ballistics of the Spring Piston Airgun:
https://www.researchgate.net/publication/274638905_Internal_Ballistics_of_Spring_Piston_Airguns (https://www.researchgate.net/publication/274638905_Internal_Ballistics_of_Spring_Piston_Airguns)
Some of the equations are a little complicated, but read the text and try to understand the discretization process that gets you a mathematical model that yields not only lots of information, but also great insights on where the guns can be improved.
If you don't want to believe the serious people that write about this, or the maths involved, then I guess that for you it will always stay in the realm of theory.
JMHO
HM
A good read. Thanks for the reference.
.
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An even better read is the followup paper that details more about bounce, including spring reverb and vibration showing how a shockwave is sent back along the spring when the piston collides at the chamber end. Good pictograms from the simulation studies.
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Hector
Thanks-exactly what I was looking for
Charlie
PS What search term/terms did you use.
I just searched again and the only hits were MY post and your post-not the great post with the info
I used
chamber diameter zero threads
diameter-found my your post
How did you find that post? search term used??
double thanks-
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An even better read is the followup paper that details more about bounce, including spring reverb and vibration showing how a shockwave is sent back along the spring when the piston collides at the chamber end. Good pictograms from the simulation studies.
I got lost in the differential equations... :o Never got past Trig and Analytic Geometry.
You have a link to the follow up paper, or is it right there with the first one?
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If you have a chronograph, you can use it to help determine an optimum weight for the particular power plant. Try a range of different weights and you will find a bell curve where very light and very heavy pellets produce less energy (fpe) than those in the middle of the range. Many folks find that the most accurate is often one of those producing the highest energy. Mind you, it's not going to make a tin of Gamo or Daisy pellets magically hit a dime at 50 yards, rather talking about quality pellets like JSB AND H&N.
But I agree with others who said shoot that which is most accurate, period, and don't worry too much about the spring.
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Very good thread, I'm always learning something when I come to the GTA. My head almost exploded with the math, but I'm better now. still, very good thread. Thanks everyone.
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Great stuff-good article
So the pellet takes 8/1000 second to break the resistance of the skirt-and start to move
and the pellet is in the barrel for about 1/100 second
and -no accident I guess-the pellet leaves the barrel just as the piston seal reaches the breech
Waaay too heavy a pellet-and the piston/seal MIGHT hit the breech BEFORE the pellet exits-
meaning it will bounce back-dropping the pressure-dropping peak velocity
Too light a pellet- or too little skirt resistance-and MAYBE- the pellet will leave the barrel BEFORE the piston gets it full stroke-leaving energy on the table
Great stuff-clever folks
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If you have a chronograph, you can use it to help determine an optimum weight for the particular power plant. Try a range of different weights and you will find a bell curve where very light and very heavy pellets produce less energy (fpe) than those in the middle of the range. Many folks find that the most accurate is often one of those producing the highest energy. Mind you, it's not going to make a tin of Gamo or Daisy pellets magically hit a dime at 50 yards, rather talking about quality pellets like JSB AND H&N.
But I agree with others who said shoot that which is most accurate, period, and don't worry too much about the spring.
I go one step further, and look for where the peak KE and peak momentum overlap.
.
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Of course, you still have to hit what you are aiming at ...
.
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An even better read is the followup paper that details more about bounce, including spring reverb and vibration showing how a shockwave is sent back along the spring when the piston collides at the chamber end. Good pictograms from the simulation studies.
Kim;
Stija's post was about the existence of the rebound. So the first of Domingo's papers was the one to suggest. Yes the second explores why people should be wary of guns without a spring guide (which is usually the case with low powered, end of the low spectrum guns, but that in recent years has been creeping up because designers want to use the same design for Gas Struts/Gas Springs and metal coil spring powered guns).
Thanks for pointing that second paper to the community.
Keep well and shoot straight.
Héctor
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Hector
Thanks-exactly what I was looking for
Charlie
PS What search term/terms did you use.
I just searched again and the only hits were MY post and your post-not the great post with the info
I used
chamber diameter zero threads
diameter-found my your post
How did you find that post? search term used??
double thanks-
In GTA you need to search for : "Specs of compression chambers" .
You could also have found the original Russian source by Googling "Compression chamber and Piston Dimensions".
Anyway, the strength of a community lies in the diversity of its members, that's how we help each other.
Keep well and shoot straight!
Héctor
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An even better read is the followup paper that details more about bounce, including spring reverb and vibration showing how a shockwave is sent back along the spring when the piston collides at the chamber end. Good pictograms from the simulation studies.
I got lost in the differential equations... :o Never got past Trig and Analytic Geometry.
You have a link to the follow up paper, or is it right there with the first one?
https://www.researchgate.net/publication/277953420_Spring_Buzz_and_Failure_in_Spring_Piston_Airguns (https://www.researchgate.net/publication/277953420_Spring_Buzz_and_Failure_in_Spring_Piston_Airguns)
HTH
Héctor
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An even better read is the followup paper that details more about bounce, including spring reverb and vibration showing how a shockwave is sent back along the spring when the piston collides at the chamber end. Good pictograms from the simulation studies.
Kim;
Stija's post was about the existence of the rebound. So the first of Domingo's papers was the one to suggest. Yes the second explores why people should be wary of guns without a spring guide (which is usually the case with low powered, end of the low spectrum guns, but that in recent years has been creeping up because designers want to use the same design for Gas Struts/Gas Springs and metal coil spring powered guns).
Thanks for pointing that second paper to the community.
Keep well and shoot straight.
Héctor
The original post was about the effect of heavier pellets in a springer, and the second paper addresses an important aspect of that.
But these posts tend to take a walk about anyway, and it is always good to explore new stuff.
Thanks again for bringing the papers to light here.
.
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So if there's bounce back, that attempts to create a vacuum and slow down heavier pellets, wouldn't a gun with a shorter barrel, like the RWS compact models, be beneficial to those who like to shoot heavier pellets?
I've always had a theory like this in pb's, that a light bullet needs a longer barrel than a heavy bullet for complete powder burn due to the difference in acceleration and time spent in the barrel.
I believe this line of thinking could lead to more barrel chopping in springers.
I had often thought of taking a chainsaw to my AirHawk to slenderize, lighten, and shorten the stock. Now I'm sure a hacksaw should've been a part of the master plan also.
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I noticed that in one of those papers
The HEAVIER pellets took LESS force to break away start moving from the breech/chamber(force the too wide skirt into lands)
2.8 kg(6 lbs) 1.8kg(4lbs force)
JSB obviously does this intentionally so both pellets-heavy and light-will start about the same time- 8/1000 second
and leave the barrel about the same time 10.8/1000 seconds
Guessing that at bounce back 9.6/1000 seconds-
and after the bounce-the pressure in the barrel is still pretty high-so cutting the barrel much shorter will drop velocity
JSB clever folks- decrease how hard it is to bend the skirt for heavier pellets so they will start to move when the piston is in the same place-
JSB whoever they are-are waaay ahead of me when it comes to pellets and velocity and air guns-no surprise
I wonder if lower priced manufacturers take the same care in skirt design-or more importantly the precision of pellet after pellet getting squashed into the barrel with the same force-tiny tiny differences in skirt thicknesses would change how much force was required
JSB clever -no wonder you fanatics love their pellets-
Guessing my lead free crosman pellets-not as good at that
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Hey Charles,
This maybe a dumb question but my concern with the too wide pellets (especially in break barrels) is the residue I get from closing the breech. I've even stopped using some types because of the damage to the pellet skirt and left over lead in the breech itself.
Wouldn't this cause a minute change in the weight of the pellet itself? and this coupled with the possible deformity of the pellet lead to inconsistent shooting?
perhaps i'm pulling hairs but I am curious....
-
Can pellets be too heavy for a particular springer?
YES!
Can pellets be too light for a particular springer?
YES!
Can this damage the springer?
YES!
How long do you want YOUR springer and/or scope to last and shoot accurately?
YOUR CHOICE!
If I read this answer I'm almost afraid to even use my springer at all LOL
I go for Benjihunter's answer: Use the pellets that gives you best accuracy.
And the Baracuda's are fine...
LOL!!! I'm laughing because my eldest brother, who got me on this slippery slope, recently chastised me for all the shooting I do in my basement with my air guns. He said "You're going to wear out your guns if you keep shooting them like that." I looked him straight in the eye and said, "I want to be known as the guy who wore out his air rifle!"
I got into this hobby to SHOOT, not to have bunch of guns to look at in their racks. If I destroy a spring here or a seal there, that's the opportunity I look forward to in order to learn how to replace the worn out parts.
FWIW, my Benji's like heavier pellets...they seem to group better, and have more retained energy at distance for the units I hunt with. The dead squirrels attest to that. Look at Chairgun Pro and run your numbers is you're going to hunt your gun. Energy at distance is important for humane kills.
I can hardly wait until I break/wear out my very first air gun. LMBO!!!
It's all about having fun, and I'm having a blast. I respect the input from the seasoned veterans here, but I guess this old guy is just concerned with having a good time and learning something new every day. YMMV.
Joe
I am with you as I have a 1968 model 1400 crosman pumper and I know its not a springer but I am still trying to wear it out after 48 years with the first ten years it was used everyday and I would not hesitate to say it has well over 100,000 pellets down its barrel and still as strong and accurate as its first shot.
Its all about having fun and enjoying what we own and I am with you on the if it breaks I can learn how to fix it as another enjoyment of the sport as well.
Sometimes you just got to give in and not let the worries consume the pleasure of why we do this to start with " FUN ".
Mike
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Kinda makes you wonder, if you can mitigate the increased spring wear induced by heavy pellets, by just using a pellet seat tool.
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Luke
I think you are asking me(caution here-I'm inexperienced in air guns-but experienced reading semi technical science-ish-academic
jargon) I looked over those two papers-one describes what happens in a spring gun
the other suggests a spring guide might increase spring life-(making spring vibrations less "banging" destructive)
But your question-
Leaving-cutting lead from pellet skirt-is as you suggest-BAD
Means your pellets are too brittle -
or your rifle has a problem with what in a powder gun would be the loading ramp/breech/throat like-"thing"
It is too sharp-should be smooth- or it doesn't allow them to fully seat-
MAYBE that is what BryanH is suggesting with a pellet seat tool-get it to seat fully-so the breech doesn't "Smush" "cut" the lead skirt-a nice tight fit barrel to receiver-should be a good thing?
lead is used for all sorts of things because it stays together-isn't brittle like Aluminum for instance-when stretched or "hit"
-you can stretch it bang it-and it thins but doesn't break or tear-
like gold silver but not quite as good but soooo much cheaper-and dense
maybe that seating tool of bryanH-or some carefully thought out modification of the seating area
Luck
Charlie
Hey Charles,
This maybe a dumb question but my concern with the too wide pellets (especially in break barrels) is the residue I get from closing the breech. I've even stopped using some types because of the damage to the pellet skirt and left over lead in the breech itself.
Wouldn't this cause a minute change in the weight of the pellet itself? and this coupled with the possible deformity of the pellet lead to inconsistent shooting?
perhaps i'm pulling hairs but I am curious.
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In a properly chamfered breach, the skirt is not quite fully inserted into the bore, and it requires pressure to "pop" the skirt passed the chamfer. That allows peak pressure to build, boosting velocity. With heavier ammo, in some guns you may have increased rebound and oscillation... maybe a pellet seat that fully inserts the skirt into the bore can make up for that. Maybe even with the right balance of weight, you can still get it moving at peak pressure with minimum rebound and oscillation?. Presuming you actually found that absolute perfect balance. It would probably be darn near impossible to find a pellet that balances this perfectly and adjust it that well. That's why you have to let the rifle choose the pellet, and then adjust the gun- then sometimes pellet test again if you are that compulsive about finding extreme optimum performance. But, you can't just pick a pellet and fiddle with it and make it work. I mean, you probably can, but it won't be near optimum performance. I would much prefer to test a handful of pellets during break in, and hold what I've got after a tune unless accuracy falls off.
But anyway, my point is, that a pellet seat tool might open up some new options for a given rifle. Maybe even a necessity for a rifle without a chamfered breach, especially with a tight bore.
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BryanH
Good point-you have to search for the right pellet.
I just closely looked at my 460
and where the receiver meets the barrel-
the sliding "bolt" is deeply countersunk
and there is a seal-light blue-translucent-that actually meets the pellet
NOT metal to metal -
it is pellet skirt to synthetic "plastic/rubber"seal- seal so nice soft air tight meeting
I don't have a break barrel-but on my 460 -just as you say-the skirt sticks out maybe 1/2mm 1/4mm -enough to see easily
Luke-on your break barrel-what actually meets the pellet-seals it-where it meets the "bolt"-metal or something soft-like a seal?
as you say-shaving pieces off the pellet skirt-
That CAN'T be right
Oh-the chamfer on the 460-is there-but via eyeball-it is very subtle -drop pellet in-and it is obvious-no pellet-tough to see that very slight taper-flare
Luke could your barrel be maladjusted-or is some seal cockeyed-
my 460 has a nice seal meeting the skirt-no metal(might be why it is pricy-the counter sunk bolt-and the nice seal-and that nice trigger-and the nice wood-heck-lotta reasons it isn't cheap)
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Oh I forgot to adress that- if the edge of your skirt ever gets clipped or smeared on closing, and you can't seat them flush with your fingertips, then a pellet seat is absolutely essential. You can experiment with different ball point pens and etc. or just buy a commercial one. I made one out of a field point and a dowel one time for a .25. Maybe you find the seating depth that works and give it a few wraps of tape to prevent inserting past a given point. Experiment! That's half the fun...
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In a properly chamfered breach, the skirt is not quite fully inserted into the bore, and it requires pressure to "pop" the skirt passed the chamfer. That allows peak pressure to build, boosting velocity. With heavier ammo, in some guns you may have increased rebound and oscillation... maybe a pellet seat that fully inserts the skirt into the bore can make up for that. Maybe even with the right balance of weight, you can still get it moving at peak pressure with minimum rebound and oscillation?. Presuming you actually found that absolute perfect balance. It would probably be darn near impossible to find a pellet that balances this perfectly and adjust it that well. That's why you have to let the rifle choose the pellet, and then adjust the gun- then sometimes pellet test again if you are that compulsive about finding extreme optimum performance. But, you can't just pick a pellet and fiddle with it and make it work. I mean, you probably can, but it won't be near optimum performance. I would much prefer to test a handful of pellets during break in, and hold what I've got after a tune unless accuracy falls off.
But anyway, my point is, that a pellet seat tool might open up some new options for a given rifle. Maybe even a necessity for a rifle without a chamfered breach, especially with a tight bore.
BryanH
Good point-you have to search for the right pellet.
I just closely looked at my 460
and where the receiver meets the barrel-
the sliding "bolt" is deeply countersunk
and there is a seal-light blue-translucent-that actually meets the pellet
NOT metal to metal -
it is pellet skirt to synthetic "plastic/rubber"-
I don't have a break barrel-but on my 460 -just as you say-the skirt sticks out maybe 1/2mm 1/4mm -enough to see easily
Luke-on your break barrel-what actually meets the pellet-seals it-where it meets the "bolt"-metal or something soft-like a seal?
as you say-shaving pieces off the pellet skirt-
That CAN'T be right
Oh-the chamfer on the 460-is there-but via eyeball-it is very subtle -drop pellet in-and it is obvious-no pellet-tough to see that very slight taper-flare
Luke could your barrel be maladjusted-or is some seal cockeyed-
my 460 has a nice seal meeting the skirt-no metal(might be why it is pricy-the counter sunk bolt-and the nice seal-and that nice trigger-and the nice wood-heck-lotta reasons it isn't cheap)
Bryan H, Phoebeisis,
What i believe happens is a 'shearing' effect from the closure of the barrel and it only happens with certain pellets. I have no issues with my H&N Barracuda 10.65 but the Gamo Hunter 15.(something) and Eujin 21 grain I have issues with.
now I've made a pellet seater and when i do this, there is no residue/scrapings after i close the breech and reopen.
As far as i see, what meets the seal (around the pellet) is metal and not another seal... i'm gonna try uploading some photos maybe the wizards here could determine if i have an issue. i'm still within warranty period, though I have some misgivings about my local hatsan dealer...
these shavings could also be because of the diameter of my barrel being (lets say) 4.50 and not 4.53 etc...i'm considering jimming up a pellet sizer and using it on all my problematic pellets before use.
i've done some crude measurements and things do seem to line up..i'll try adjusting my phone's picture size/format to make the photos small enough to upload
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Hi Bryan,
My seater is made from a filed nail extending from handle made from Guava wood...the nail extends a max of 1 cm and the handle is wide enough that it prevents it from going in deeper
i have alot of photos to upload i'll include this on my list. lol!
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Its been my experience with my break barrels and underlever/sidelever spring guns that if the pellet is being clipped because its not seating fully by hand then seating it just inside the barrel bore will prevent that from happening but the farther you deep seat it past the end of the barrels bore the more you will cause velocity to be lost in proportion to the seating depth at least in my guns. I have tried it in all my spring guns from the cheap crosmans to my FWB 124, 300s, B40 and D48 and lost up to 50 fps in every gun with no seen gains in accuracy or any other benefit so I do not seat past what I can do with my finger but then I don't have a clipping issue either with any gun.
I would address the clipping issue by slightly chamfering the leade so that the best pellet the gun likes seats fully by use of your fingers and ends up just flush or a thousands or two below flush so as to not create any excess air space between the back of the pellet and transfer port. The deeper the pellet is seated the more the air has to be compressed behind the pellet to start the pellet moving and therefore the loss of velocity.
Mike
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Interesting stuff
Odd that the break barrels haven't/don't have some sort of soft seal like my under levers-
the under levers B3 and 460 both have a moving "bolt" that allow the seal to soft seal the transfer port to pellet skirt junction
the break barrels don't have the same sort of set up?
These-not great pictures
show the orange cup like seal on the B3-it looks worn where it meets skirt-despite just 200 rds over 20 years
and the blue button like seal on the 460
Maybe the pictures are clear enough?
PS Took my "life in my hands" finger wise-touching the B3 rubber seal to see if it was actually rubbery(it is)-no bear trap safety on it-$20 in 1995-can't complain-yes I had to lever firmly held-
How do break barrels seal the transfer port to rear of breech junction?? to keep it air tight during air discharge ?
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Oring around the chamber.
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39m
Thanks.
My under levers seal right at or around the pellet-
the last 1/3" of the barrel is enclosed by that countersunk "bolt"-
seals the barrel transfer port-and maybe actually touches the skirt
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39m
Thanks.
My under levers seal right at or around the pellet-
I don't have one, but here's a picture. Curiously with a damaged pellet stuck in the chamber.
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39
Thanks-great picture
but YIKES tore the skirt off-blew the head down the barrel-left the skirt?
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So if there's bounce back, that attempts to create a vacuum and slow down heavier pellets, wouldn't a gun with a shorter barrel, like the RWS compact models, be beneficial to those who like to shoot heavier pellets?
I've always had a theory like this in pb's, that a light bullet needs a longer barrel than a heavy bullet for complete powder burn due to the difference in acceleration and time spent in the barrel.
I believe this line of thinking could lead to more barrel chopping in springers.
I had often thought of taking a chainsaw to my AirHawk to slenderize, lighten, and shorten the stock. Now I'm sure a hacksaw should've been a part of the master plan also.
Interesting point of view!
Of course you know what the real answer is: Get a compact and do some research.
There have been worthwhile experiments cutting the barrel progressively and analyzing the performance, but not in rifles with decent sized compression chambers.
And comparing two different guns always leaves the researcher with the idea that perhaps the guns were not identical to start with, something that happens a LOT in breakbarrel, long transfer port rifles.
The PB's analogy is not as good as it sounds because modern coated powders have an inversely related burn rate. If the bullet is too heavy, peak pressure will be achieved earlier into the bullet's travel through the barrel, which means that most of the acceleration will be gained in the first ¼, but light bullets will keep the pressure rising up to about ½ the barrel length. In the end, the AREA UNDER THE CURVE Pressure vs. barrel travel will be almost identical. Blast and Flash will be different, of course, as anyone that has fired a short barreled magnum knows.
So, get a hacksaw or get a compact and let us know.
;)
Keep well and shoot straight!
Héctor
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39
Thanks-great picture
but YIKES tore the skirt off-blew the head down the barrel-left the skirt?
Apparently, that picture came from this article,
https://www.pyramydair.com/article/How_to_load_pellets_in_airguns_Part_1_spring_piston_guns_November_2010/80 (https://www.pyramydair.com/article/How_to_load_pellets_in_airguns_Part_1_spring_piston_guns_November_2010/80)
explaining how to load a pellet. I never dreamed that there would be a whole article written on how to load a pellet. But there it is.
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So if there's bounce back, that attempts to create a vacuum and slow down heavier pellets, wouldn't a gun with a shorter barrel, like the RWS compact models, be beneficial to those who like to shoot heavier pellets?
I've always had a theory like this in pb's, that a light bullet needs a longer barrel than a heavy bullet for complete powder burn due to the difference in acceleration and time spent in the barrel.
I believe this line of thinking could lead to more barrel chopping in springers.
I had often thought of taking a chainsaw to my AirHawk to slenderize, lighten, and shorten the stock. Now I'm sure a hacksaw should've been a part of the master plan also.
Interesting point of view!
Of course you know what the real answer is: Get a compact and do some research.
There have been worthwhile experiments cutting the barrel progressively and analyzing the performance, but not in rifles with decent sized compression chambers.
And comparing two different guns always leaves the researcher with the idea that perhaps the guns were not identical to start with, something that happens a LOT in breakbarrel, long transfer port rifles.
The PB's analogy is not as good as it sounds because modern coated powders have an inversely related burn rate. If the bullet is too heavy, peak pressure will be achieved earlier into the bullet's travel through the barrel, which means that most of the acceleration will be gained in the first ¼, but light bullets will keep the pressure rising up to about ½ the barrel length. In the end, the AREA UNDER THE CURVE Pressure vs. barrel travel will be almost identical. Blast and Flash will be different, of course, as anyone that has fired a short barreled magnum knows.
So, get a hacksaw or get a compact and let us know.
;)
Keep well and shoot straight!
Héctor
I'm really not into proving theory. But having ideas about how things work helps me with my choices.
Mainly I just like to shoot.
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So if there's bounce back, that attempts to create a vacuum and slow down heavier pellets, wouldn't a gun with a shorter barrel, like the RWS compact models, be beneficial to those who like to shoot heavier pellets?
I've always had a theory like this in pb's, that a light bullet needs a longer barrel than a heavy bullet for complete powder burn due to the difference in acceleration and time spent in the barrel.
I believe this line of thinking could lead to more barrel chopping in springers.
I had often thought of taking a chainsaw to my AirHawk to slenderize, lighten, and shorten the stock. Now I'm sure a hacksaw should've been a part of the master plan also.
Interesting point of view!
Of course you know what the real answer is: Get a compact and do some research.
There have been worthwhile experiments cutting the barrel progressively and analyzing the performance, but not in rifles with decent sized compression chambers.
And comparing two different guns always leaves the researcher with the idea that perhaps the guns were not identical to start with, something that happens a LOT in breakbarrel, long transfer port rifles.
The PB's analogy is not as good as it sounds because modern coated powders have an inversely related burn rate. If the bullet is too heavy, peak pressure will be achieved earlier into the bullet's travel through the barrel, which means that most of the acceleration will be gained in the first ¼, but light bullets will keep the pressure rising up to about ½ the barrel length. In the end, the AREA UNDER THE CURVE Pressure vs. barrel travel will be almost identical. Blast and Flash will be different, of course, as anyone that has fired a short barreled magnum knows.
So, get a hacksaw or get a compact and let us know.
;)
Keep well and shoot straight!
Héctor
Another perspective is to look at the pressure chamber. I noticed when I tuned my 350 and 460 that they had very different length springs, but apparently similar swept volumes (I could be wrong there). So if they have similar volumes, producing similar muzzle energies, then the shorter spring could have compressed the volume faster. Tuning the rate of compression (spring expansion) to the pellet chamber compression and pellet travel would be of interest.
Of course many shooters do just that in de-tuning their springers to get a more manageable shooter (less recoil and bump at a lower relative power).
.
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Yep all in that never ending quest for the perfect spring gun its amazing what changes do to help or hurt the guns character and shootability or improve it to near perfection.
I know I am never satisfied and always think it can be better and have always been that way with my hot rod cars and bikes as well. Just don't know how to leave well enough alone I guess.
Mike
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39M
Right-never would have figured there was THAT much to loading a pellet
But it was a very good article
Frankly-not wanting to pick a fight
BUT-why would anyone choose a break barrel over an under lever
granted ease of loading and perhaps 4-8 ounces in weight-well those are important-my 460 sure as heck isn't light
DOKF-such a cute little pup-spaniel of some sort?
Buldawg76- know what you mean-In 1998 I sent a head from my SR500(28 hp 1980 yamaha 500 cc street single) TO FRANCE- Krautergershiem France-sure sounded germanic,but france-paid $1000 to have the intake port raised 55 degree turn instead of 71 degree turn(carb. to chamber angle) and a second plug pumbed in-
allowed it to make MAYBE 40 hp when combined with $1200 more hot rod stuff-
and it was STILL the slowest 500cc motorcycle in the WORLD-my late wife was very tolerant!
I know I probably can't beat the OEM engineers-(now I'm a mpg nut) but I still try
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My head is spinning from the amount of info here. It now brings me to question the purchase of a dual caliber air rifle. Is it wise to subject a spring to such wide variations in pellet weight?
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so I'm trying to load pics but my camera's smallest pic size is 2mb....hmm.
i think my seater is probably too long, and it's beginning to explain why i've lost some accuracy....just goes to show 'it's you not the gun'...
Capnru, there is definitely the ocean's worth of info here...
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My head is spinning from the amount of info here. It now brings me to question the purchase of a dual caliber air rifle. Is it wise to subject a spring to such wide variations in pellet weight?
With my Beeman dual caliber rifle i use the 10.5 gr. crosmans to slow it down , and it shoots them very accurately. With the .22 barrel I use the CHP 14.4 gr. with good accuracy and still plenty of power.
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Good to know Back Roads. I'm guessing then that a four grain difference will be tolerable in the long haul. STILL too much to know here, I feel like I'll never know enough.
I just want to have fun, not hurt my head.
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DOKF-such a cute little pup-spaniel of some sort?
American Cocker Spaniel. Very loyal, very friendly, loves to chase tennis balls and squirrels.
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My head is spinning from the amount of info here. It now brings me to question the purchase of a dual caliber air rifle. Is it wise to subject a spring to such wide variations in pellet weight?
Springers are all designed for an optimum muzzle energy, which dictates a range in pellet weights. There is usually a broader range of pellet weights than pellet designs that work well in any given air gun.
I try to select pellets on the heavier side of optimum to retain higher down field momentum in hunting applications.
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well, they can be, kind of. The thing is, its a little more complicated than most folks realize. What I'm saying here is based on both my experience and Jim Maccari's. The real answer depends on the wire your spring is made from. In the case of the R-9/HW95, wire diameter has been .122". The rule of thumb for .177 cal was not to go above 9.5 gr if steadily using them, because springs of .126" wire and above handle heavier pellets better. For .22 springers, the pellet weight was 16.5 gr or less for .122' wire or thinner. Again, wire .126" or thicker can reliably handle the heavier lead. OK, what happens if I exceed these recommendations? Well, nothing initially. Constant use of heavy pellets with light springs eventually shortens spring life. Most often, this translates into spring fracture. There are times when a gun will still shoot with a busted spring and the owner will not know it, except for a possible slight loss in power. Other times the spring shatters into several pieces and all of a sudden you can't get the gun to cock fully.
In the end, you have to consider the mainspring as a consumable item. They will not last forever; especially if you are a heavy user. If you're trying to stretch the life of your R-9 spring, then keep pellet weight between 7.9 and 9.5 grains for .177. In .22, stay between 11 and 16.5 gr. .20 cal? Keep them between 11 and 14.3 gr.
Bigger guns like the R-1/HW80; Beeman Kodiak/Patriot, Webley Tomahawk (UK) have much heavier springs and can handle heavier lead easily.
I once published a list of guns with their wire diameters on another forum, but can't find that info anymore, although it has to be out there somewhere.
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It all seems pretty simple at first; point and shoot.
But the more you delve into it, the more complicated it can get. Springs, seals, lubes, pellet weight, pellet design ...
Optimize what you can, then point and shoot.
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My head is spinning from the amount of info here. It now brings me to question the purchase of a dual caliber air rifle. Is it wise to subject a spring to such wide variations in pellet weight?
It will be fine. Most models have the same spring specifications in different cals. Stick with ammo in the ballpark of 8 grains in .177, plus or minus a grain, and 14 grains in .22, plus or minus two grains. Your gun will be fine.
I feel like we have you worried for nothing. Just pick the most accurate off the shelf pellet in your gun and you should have zero issues. Is the extra tin or two you get out of a spring worth it, if you miss things you woukd have hit with another more accurate pellet? Not to me. A spring swap is a fifteen minute ordeal.
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When I first got into airguns, one of the first things I read was over on CharlieDaTuna's website about using pellets no larger than about 8 grains because it can damage your spring.
Is this true?
I've just ordered a HW95 from AoA, with a box of 10.65 grain Baracuda Match H&N pellets. Maybe I should have stayed below 8 grains?
What do you think?
Kinda late to this party but I have some first hand info concerning CP heavies (10.5 grain) in an R9. When I first introduced my brother to airguns decades ago by selling him one of my home tunes .177 R9s he shot only CP heavies since they were very accurate and they would drive 3/4 way through a grey squirrel LONG WAYS after busting some larger bones. Because of this he had the skill to angle a CP heavy through the vitals of a squirrel from any angle! LOL....when cleaning squirrels with my brother there was one grey squirrel that was hit at the right hip and the CP heavy drove longways through and we found the mangled pellet lodged in the spine at the neck. Here are two 50 yard 3 shot groups (was shooting typical powder burner groups) he shot "back to back" with the R9 I sold him and CP heavies.......
(http://www.snapagogo.com/uploads/source/2352014/1408919562_2034562871_HenryTarget.jpg) (http://www.snapagogo.com/photo.php?id=56424)Uploaded at Snapagogo.com (http://"http://www.snapagogo.com")
Shooting "heavies" I used to replace his good Maccari aftermarket spring about every two years shooting about a box of CPs a month. After shooting heavies for several years he found that the flatter trajectory of the 7.9 grain CP light trumped the slightly better wind resistance and deep driving CP heavy. After switching to CP lights I only replace one Maccari spring in several years and that spring spent half of it's "life" shooting CP heavies. After replacing that spring with a new Maccari Tarantula spring (my favorite variety no longer being sold) he never replaced it after several years of shooting when I moved to North Carolina.
Anywhoo........I've never shot pellets heavier than 8.6 grains from my R9 and heavier than 8.4 grains with my HW95 because I also believe that the flatter trajectory of the "light" pellet as more useful than the "heavy" pellet. One thing to consider is that mainsprings are indeed considered "consumables" to be replaced on occasion and with the R9/HW95 a simple spring swap can be done in less than 1/2 hour for about $20 (if you opt for the really good Maccari springs) and you're good for several years more frequent shooting! IMHO....if you don't mind replacing a spring every couple years simply shoot the "heavy pellets" IF they are indeed more accurate for you under field conditions!
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Another perspective is to look at the pressure chamber. I noticed when I tuned my 350 and 460 that they had very different length springs, but apparently similar swept volumes (I could be wrong there). So if they have similar volumes, producing similar muzzle energies, then the shorter spring could have compressed the volume faster. Tuning the rate of compression (spring expansion) to the pellet chamber compression and pellet travel would be of interest.
Of course many shooters do just that in de-tuning their springers to get a more manageable shooter (less recoil and bump at a lower relative power).
.
You are quite right in that the 460 is the fixed barrel version of the 350, but the MAIN difference between them is not what is used as a cocking lever, the REAL difference is that between the front end of the piston at the end of its travel and the pellet's base in the 460 you have a short transfer port and in the 350 you have a long transfer port.
If you look into the papers we are discussing you can see that the "dead space" that the long transfer port creates creates a large difference between how the two guns need to operate to obtain the best performance.
On the "de-tuning", what is funny, Kim, is that sometimes "De-tuning" can yield the SAME results of a "Full Power" rifle.
Springers are EXTREMELY sophisticated machines and by making a number of small changes you can get all that is needed and leave behind everything that is not.
Please read the blog entry: http://www.ctcustomairguns.com/hectors-airgun-blog/the-wide-and-wonderful-range-of-a-short-stroked-d-54 (http://www.ctcustomairguns.com/hectors-airgun-blog/the-wide-and-wonderful-range-of-a-short-stroked-d-54)
Where I show that the combination of a good piston (to reduce piston re-bound), a reduced stroke (to reduce coil clash and inverse pressure spikes), a proper breech seal (to position the pellet EXACTLY where the cycle needs it), and proper inside/outside guides, plus a moved fulcrum point in the cocking lever, can give you full 15½ ft-lbs of muzzle energy with barely 23 lbs cocking effort.
You get power, smoothness, accuracy, reliability and consistency and you leave behind harshness, buzz, sore shoulders, broken springs and burnt seals.
Sometimes, less IS more.
;)
Keep well and shoot straight!
Héctor Medina
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39M
Right-never would have figured there was THAT much to loading a pellet
But it was a very good article
Frankly-not wanting to pick a fight
BUT-why would anyone choose a break barrel over an under lever
granted ease of loading and perhaps 4-8 ounces in weight-well those are important-my 460 sure as heck isn't light
DOKF-such a cute little pup-spaniel of some sort?
Buldawg76- know what you mean-In 1998 I sent a head from my SR500(28 hp 1980 yamaha 500 cc street single) TO FRANCE- Krautergershiem France-sure sounded germanic,but france-paid $1000 to have the intake port raised 55 degree turn instead of 71 degree turn(carb. to chamber angle) and a second plug pumbed in-
allowed it to make MAYBE 40 hp when combined with $1200 more hot rod stuff-
and it was STILL the slowest 500cc motorcycle in the WORLD-my late wife was very tolerant!
I know I probably can't beat the OEM engineers-(now I'm a mpg nut) but I still try
Charles
Yep know exactly what you mean but back in the seventies and eighties I was a two stroke man and rode Yamahas exclusively starting with a 175 endure and ending up with a 74 SC500 single cylinder 500cc two stroke that weighed 210 pounds and made 45 HP at the rear tire to the ground with 4 gears and factory sprockets would do 105 mph in less than an 1/8 mile. It was only built 1 1/2 years by them from half of 73 and all of 74 and was designed to run the Baja 1000. I still have that bike but due to age and health cannot even consider riding it anymore but just cant make myself get rid of it as it just about killed me more time than I can count since it would accelerate far faster than it would stop on the skimpy drum brakes of the day.
My current scoots now are a 77 model KZ 1000 built to run quarter miles in 9.5 seconds with the slick and wheelie bar but its been converted to street use to play with the new crotch rockets from stop light to stop light and a 76 shovelhead that makes Evos and Twin Cammers mad when I walk away from them on the highway since they top out at around 110 mph and my shovel is just getting up on the cam at 120 mph and is only at 5300 rpm and pulling hard to a 6000 rpm redline.
But still not done with either one as far as more upgrades are in the works for both of them.
I am just stuck in the 70s as far as vehicle go.
Mike
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Ha,ha
In one of those australian "MAD MAX" movies
which had LOTS of great bikes-safe bet some version of the Kawasaki 900-1000 was featured I think
Well there was an old HOT ROD saying posted in a hot rod garage
It said something to the effect
"Tell me how much money you have and I'll tell you how fast you can go"
something like your 2 stroke 500 Yamaha "enduro"-that vintage with anything like the stock drums-and with the suspension frame limitations of that time-well it would have been an example of that saying
But the 9.5 SECOND kawasaki-even MORE $$-much more!
Ha!
You are LUCKY to still be alive!!
That 500 YAMAHA would have been a KILLER BIKE -in EVERY WAY!!
The Kawasaki 1000--real brakes and lower CG-much "safer" if a 9.5 second bike is "safer"
About 5 years ago-finances- age-cell phones texting-late wife's illness-I sold that SR500- over the years I owned 11 different ones-and some of them-literally the same bike-I bought re-bought -more than ONCE-
Yeah crazy for cars-trucks-SUV-motorcycles-bicycles too-guns too-
dogs and cats too I guess\
It is a disease-no cure-
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When I first got into airguns, one of the first things I read was over on CharlieDaTuna's website about using pellets no larger than about 8 grains because it can damage your spring.
Is this true?
I've just ordered a HW95 from AoA, with a box of 10.65 grain Baracuda Match H&N pellets. Maybe I should have stayed below 8 grains?
What do you think?
Kinda late to this party but I have some first hand info concerning CP heavies (10.5 grain) in an R9. When I first introduced my brother to airguns decades ago by selling him one of my home tunes .177 R9s he shot only CP heavies since they were very accurate and they would drive 3/4 way through a grey squirrel LONG WAYS after busting some larger bones. Because of this he had the skill to angle a CP heavy through the vitals of a squirrel from any angle! LOL....when cleaning squirrels with my brother there was one grey squirrel that was hit at the right hip and the CP heavy drove longways through and we found the mangled pellet lodged in the spine at the neck. Here are two 50 yard 3 shot groups (was shooting typical powder burner groups) he shot "back to back" with the R9 I sold him and CP heavies.......
(http://www.snapagogo.com/uploads/source/2352014/1408919562_2034562871_HenryTarget.jpg) (http://www.snapagogo.com/photo.php?id=56424)Uploaded at Snapagogo.com (http://"http://www.snapagogo.com")
Shooting "heavies" I used to replace his good Maccari aftermarket spring about every two years shooting about a box of CPs a month. After shooting heavies for several years he found that the flatter trajectory of the 7.9 grain CP light trumped the slightly better wind resistance and deep driving CP heavy. After switching to CP lights I only replace one Maccari spring in several years and that spring spent half of it's "life" shooting CP heavies. After replacing that spring with a new Maccari Tarantula spring (my favorite variety no longer being sold) he never replaced it after several years of shooting when I moved to North Carolina.
Anywhoo........I've never shot pellets heavier than 8.6 grains from my R9 and heavier than 8.4 grains with my HW95 because I also believe that the flatter trajectory of the "light" pellet as more useful than the "heavy" pellet. One thing to consider is that mainsprings are indeed considered "consumables" to be replaced on occasion and with the R9/HW95 a simple spring swap can be done in less than 1/2 hour for about $20 (if you opt for the really good Maccari springs) and you're good for several years more frequent shooting! IMHO....if you don't mind replacing a spring every couple years simply shoot the "heavy pellets" IF they are indeed more accurate for you under field conditions!
Ed, is this the tarantula spring you liked? This is still available.
http://www.airrifleheadquarters.com/catalog/item/251488/43410.htm (http://www.airrifleheadquarters.com/catalog/item/251488/43410.htm)
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When I first got into airguns, one of the first things I read was over on CharlieDaTuna's website about using pellets no larger than about 8 grains because it can damage your spring.
Is this true?
I've just ordered a HW95 from AoA, with a box of 10.65 grain Baracuda Match H&N pellets. Maybe I should have stayed below 8 grains?
What do you think?
Kinda late to this party but I have some first hand info concerning CP heavies (10.5 grain) in an R9. When I first introduced my brother to airguns decades ago by selling him one of my home tunes .177 R9s he shot only CP heavies since they were very accurate and they would drive 3/4 way through a grey squirrel LONG WAYS after busting some larger bones. Because of this he had the skill to angle a CP heavy through the vitals of a squirrel from any angle! LOL....when cleaning squirrels with my brother there was one grey squirrel that was hit at the right hip and the CP heavy drove longways through and we found the mangled pellet lodged in the spine at the neck. Here are two 50 yard 3 shot groups (was shooting typical powder burner groups) he shot "back to back" with the R9 I sold him and CP heavies.......
(http://www.snapagogo.com/uploads/source/2352014/1408919562_2034562871_HenryTarget.jpg) (http://www.snapagogo.com/photo.php?id=56424)Uploaded at Snapagogo.com (http://"http://www.snapagogo.com")
Shooting "heavies" I used to replace his good Maccari aftermarket spring about every two years shooting about a box of CPs a month. After shooting heavies for several years he found that the flatter trajectory of the 7.9 grain CP light trumped the slightly better wind resistance and deep driving CP heavy. After switching to CP lights I only replace one Maccari spring in several years and that spring spent half of it's "life" shooting CP heavies. After replacing that spring with a new Maccari Tarantula spring (my favorite variety no longer being sold) he never replaced it after several years of shooting when I moved to North Carolina.
Anywhoo........I've never shot pellets heavier than 8.6 grains from my R9 and heavier than 8.4 grains with my HW95 because I also believe that the flatter trajectory of the "light" pellet as more useful than the "heavy" pellet. One thing to consider is that mainsprings are indeed considered "consumables" to be replaced on occasion and with the R9/HW95 a simple spring swap can be done in less than 1/2 hour for about $20 (if you opt for the really good Maccari springs) and you're good for several years more frequent shooting! IMHO....if you don't mind replacing a spring every couple years simply shoot the "heavy pellets" IF they are indeed more accurate for you under field conditions!
Ed, is this the tarantula spring you liked? This is still available.
http://www.airrifleheadquarters.com/catalog/item/251488/43410.htm (http://www.airrifleheadquarters.com/catalog/item/251488/43410.htm)
No....the old Tarantula spring was around 30-32 coils (I don't remember exactly) of .128 wire wound with a .540 inside diameter. I did recently order 4 new Maccari springs like this..........
(http://www.snapagogo.com/uploads/source/3452015/1449924168_1281150010_E3650Spring1.jpg) (http://www.snapagogo.com/photo.php?id=78970)Uploaded at Snapagogo.com (http://"http://www.snapagogo.com")
They have a smaller ID than what I'm used to and I'm currently using one in my HW95. A spring wound with a smaller ID will be higher stressed than a similar spring wound with a larger ID, but I've had excellent spring life from Maccari springs over the years so it remains to be seen how the E3650 holds up. Since the E3650 is a .120 wire spring with 35 coils it very well may hold up as long (or longer) than the old Tarantula with .128 wire wound with a .540 ID.
Personally, over the last few years I've been tuning my R9 & HW95 to shoot 7.9 grain CPLs at 850fps (no more than 865fps) instead of 910fps like I did in the "old days". The .120 wire spring with 35 coils can still put our a CPL at 900fps is "spaced up" with my HW95 but I prefer a lower stress tune that also has a milder shot cycle which is easier to control.
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Makes since to me.
Thx Ed
T
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Ha,ha
In one of those australian "MAD MAX" movies
which had LOTS of great bikes-safe bet some version of the Kawasaki 900-1000 was featured I think
Well there was an old HOT ROD saying posted in a hot rod garage
It said something to the effect
"Tell me how much money you have and I'll tell you how fast you can go"
something like your 2 stroke 500 Yamaha "enduro"-that vintage with anything like the stock drums-and with the suspension frame limitations of that time-well it would have been an example of that saying
But the 9.5 SECOND kawasaki-even MORE $$-much more!
Ha!
You are LUCKY to still be alive!!
That 500 YAMAHA would have been a KILLER BIKE -in EVERY WAY!!
The Kawasaki 1000--real brakes and lower CG-much "safer" if a 9.5 second bike is "safer"
About 5 years ago-finances- age-cell phones texting-late wife's illness-I sold that SR500- over the years I owned 11 different ones-and some of them-literally the same bike-I bought re-bought -more than ONCE-
Yeah crazy for cars-trucks-SUV-motorcycles-bicycles too-guns too-
dogs and cats too I guess\
It is a disease-no cure-
Charles
That was "Toecutters" KZ 1000 named the "KWAKA" in the original Mad Max movie and yes it is a classic at its best. My Kawi is in fact much safer than the older 500 MX with the drum brakes and very inferior suspension of the day. I started on the 175 and learned to ride it WOT everywhere then went to a 360 MX and learned to ride it WOT everywhere and then found the 500 MX and it never failed just when I thought I could ride it WOT everywhere it let me know it was not to happen so yes I am lucky to be alive as I have eaten it on that bike at 90 plus mph in the dirt but learned very early in my dirt bike days to play drunk when you fall off and let your body go limp so nothing breaks but just gets a lot of road "ah dirt rash. Dirt is really akin to sandpaper as my scars back then were proof.
The brakes on the Kawi are a good bit better than the 500's but still nowhere near what todays standards are in comparison so it can still make the hair on the back of your neck stand up at 150 mph when someone decides they want the lane you are using out on the street, but I have learned to limit my high speed runs to the interstates since at least there are no stop lights and everyone is going the same direction.
There are two sayings as you got one in that "How much money you have dictates how fast you can go" and the other one which I attribute to me still being here today is " Never ride faster than your angels can fly " I have some fast angel apparently LOL.
The Kawi has over 3500 in the motor alone to be bullet proof and go fast enough to run consistent 9.5 second quarter miles with only minor tune ups and oil changes every 1500 miles. I had it dynoed about 5 years ago and at 10,000 rpm it was making 135 HP and 124 Ft/LBs torque so it is indeed fun on the street stripped down to a mere 450 pounds full of oil and fuel.
I have always been bitten by the "Need for speed " and would rather die on a bike doing what I love than from old age but I admit I have slowed down in my old age as the fear factor level has dropped considerably as the body slows down healing from being young and dumb or ten foot tall and invincible just never figured out which it was. LOL.
I hope they don't find a cure in my lifetime anyway for cars. bikes or guns.
Mike
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Hah!!
Never ride faster than your angels' can fly
Now THAT is a good one-can't remember hearing it before!
Yeah that KAWKA was a cool bike
the early Kawasaki 900/1000 were cool looking dead stock
kinda "cobby" short stout purposeful looking is how they were described
I have a vivid-but somehow vague-of walking into a shop-and seeing a factory custom Kawasaki 1000-
it had a cafe type fairing-triple disc-greenish color-not quite olive drab-but not a color you associate with motorcycles-
but the Kawa pulled it off-it was waaaay cool
maybe one even had a factory turbo??- old memories can get mixed
about that time Kawa came out of the cross frame 6 cylinder-even BIGGER BULKIER than the Honda CBX-
I have run on-well back to air guns-
my first one was a "benjamin pump" brass etc-brother and I pulled money $6 to buy it used-parents would have killed us-we were 8 11-and "not responsible" even for 8 and 11
Those Kawasakis were cool-dead stock they looked "right" this is before the japanese went all godzilla movie style wise(but that was mainly Suzuki) -and those aussies-right at home in the USA-cars bikes wide open spaces-they wrecked some cool cars bikes in those movies-safe bet they salvaged PLENTY of parts!
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My first real bike was a Kawasaki MC90 way back when Kawasaki dirt bikes were blue. Wish I had a pic of it. My buddy had a slightly more modern yellow yz80.
We rode in the same places we hunted. Me with an an 880(back before the buttplate was removable) and him with 760 or 766 or something like that.
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39M
Funny my 1st bike was a 90cc Kawasaki also- street bike(maybe 1971) but with a high pipe I think-like an Enduro
in 1973 I had it-used it to switch from LSUBR to grad school in New Orleans
WOT did 77mph--with me doing my impression of that lying Brit that claimed they got 120 mph out of a stock Bonneville 650(nice bike but no way 120 mph-not stock-but safe bet it wasn't remotely stock)
Anyway-it would show 77mph on the speedo-with me stretched flat-legs out etc-
2 stokes-smelled a bit like a detonating air rifle-but NOISIER!!
My .22 460-had it for 3 weeks-only detonated once-when I shot a 25.7 grain H&N heavy copper jacket pellet-not much wood penetration-so must have been pretty low velocity-the noise and smell surprised me a bit-after 100 9.5 pellets and 16.4 -the super heavy one-diesel-noise smell
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Charles and 39M
My first bike was the 72 Yamaha 175 enduro that was candy apple red and was my main transportation thru high school.
Here are a couple pics of the Grunt as its known around town.
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The Grunt
Yep that fits
Cool looking bike-
"just a motorcycle" no BS plastic boy racer stuff
such BIG mufflers- ha,ha-wakes them dead when you hit it hard
and the wrapped pipes-cool
just a motorcycle-
Q-ship bike-nothing say 9.5 quarter-except the aftermarket covers on side-and wrapped pipes
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Charles
Yep its a sleeper bike and meant to be a wolf in sheep's clothing.
The pipe is an old Warrior reversion header with no baffles so yes it will wake the dead on the cam for sure.
The wrapped pipes is to retain the exhaust heat to aid in power and performance.
My wife can hear me coming 2 miles away and has the garage open when I pull in the driveway just in case I need to hide from the man. LOL
All go and no show is the way I like it.
Thanks for the compliments
Mike
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Oh and the rear fender is from a KZ 650 not the 1000 to give it more of a café look.
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Rearsets too
Hah-I was getting too old and too inflexible to bend my stubby legs up under me-so no rear sets for me
Yeah that is a SLEEPER bike!
I will have to watch the 1st Mad max movie again-
it was more a bike movie than a car movie
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Yep definitely rear sets since I always rode with my feet on the passenger pegs and only moved to rider pegs to brake or shift it was just a no brainer when I found ones that fit. race cut tranny, lock up clutch, balanced and welded crank, 1075cc kit ( soon to be 1200cc ), ported and polished head, web race cams, 36mm flat slide carbs, adjustable cam chain tensioner, Dyna S ignition with rev limiter + coils and wires, 530 chain and sprockets, Kosman lengthened drag race swingarm, 3.5 inch wide NHRA approved rear rim with tire screwed to rim, center crank main bearing cap brace, and other little tricks of the trade.
I can watch the original Mad Max movie 100 times and never be bored.
Most definitely more of a bike movie than cars.
Mike
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At some point we split the thread and let the motorcycle guys continue down an alternate path in the backroom? I mean, the title of the thread is no longer relevant to the topic...
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Which is too bad really. I don't mind motorcycle talk, but the information on springers and pellet weight is invaluable, and wouldn't like it to get buried. I'm thankful for folks like Hector who can give us much needed information and perspective on things. (Even if it's far over my head.)
I was about to ask what the FPE was on a motorcycle thread that hit a moderator? :o
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Which is too bad really. I don't mind motorcycle talk, but the information on springers and pellet weight is invaluable, and wouldn't like it to get buried. I'm thankful for folks like Hector who can give us much needed information and perspective on things. (Even if it's far over my head.)
I was about to ask what the FPE was on a motorcycle thread that hit a moderator? :o
Jim;
NOTHING is over anyone's head.
After many years of teaching maths at all levels I know that there are ways to explain things. Not "dumb them down" because that is not useful, but explaining things in terms anyone can understand.
If you have a question, I am sure others have exactly the same question. PLEASE, just ask, I will do my best to explain it in adequate terms. If it needs an extensive explanation, perhaps it would even merit an entry into the blog, ¿who knows?
My grandpa used to say that the only stupid question is the one not asked.
;)
Keep well and shoot straight!
Héctor
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So if there's bounce back, that attempts to create a vacuum and slow down heavier pellets, wouldn't a gun with a shorter barrel, like the RWS compact models, be beneficial to those who like to shoot heavier pellets?
I've always had a theory like this in pb's, that a light bullet needs a longer barrel than a heavy bullet for complete powder burn due to the difference in acceleration and time spent in the barrel.
I believe this line of thinking could lead to more barrel chopping in springers.
I had often thought of taking a chainsaw to my AirHawk to slenderize, lighten, and shorten the stock. Now I'm sure a hacksaw should've been a part of the master plan also.
Interesting point of view!
Of course you know what the real answer is: Get a compact and do some research.
There have been worthwhile experiments cutting the barrel progressively and analyzing the performance, but not in rifles with decent sized compression chambers.
And comparing two different guns always leaves the researcher with the idea that perhaps the guns were not identical to start with, something that happens a LOT in breakbarrel, long transfer port rifles.
The PB's analogy is not as good as it sounds because modern coated powders have an inversely related burn rate. If the bullet is too heavy, peak pressure will be achieved earlier into the bullet's travel through the barrel, which means that most of the acceleration will be gained in the first ¼, but light bullets will keep the pressure rising up to about ½ the barrel length. In the end, the AREA UNDER THE CURVE Pressure vs. barrel travel will be almost identical. Blast and Flash will be different, of course, as anyone that has fired a short barreled magnum knows.
So, get a hacksaw or get a compact and let us know.
;)
Keep well and shoot straight!
Héctor
Interesting, I have a 177 pro compact. I shot, exclusively, JSB 10.3 gr pellets. They were, by far, the most accurate in my rifle.
(http://i1030.photobucket.com/albums/y364/Thiggs1/Diana%2034%20facelift/image_zps2xeq0x3m.jpeg)
I only got about 2000 rounds on the factory spring. I took it out to shoot after it had been sitting idle for several months. The first shot sounded horably wrong so I stopped immediately. On inspection, my spring was broken in two places. Very odd to me! My question is, if heavy pellets can cause abnormal spring wear via bounce/vacuum, wouldn't this be a perpetual problem for the same rifle in .22 caliber since it would have the same spring, piston, and tube but would always be pushing more weight?
Here is a pic of original spring next to vortek replacement.
(http://i1030.photobucket.com/albums/y364/Thiggs1/Diana%2034%20facelift/image_zpsldx2vppg.jpeg)
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Sorry about getting sidetrack with bikes.
Back to heavy pellets in spring guns, but also related to engines since they also use springs to open and close valves. I am somewhat baffled and perplexed how the weight of the pellet has any real impact on the life of a spring and how leaving one cocked for long term degrades the spring by significant amounts.
The spring does not know what weight pellet is in the barrel since it will expand at a given rate allowed by its wire diameter and ID/OD and number of coils and amount of compression when cocked. As T-Higgs stated there are many spring guns that use the same spring, piston, guides and so on for 177, 22, 25 calibers in which you a wide variance in pellet weights per caliber of gun.
In relation a motor vehicle engine uses coil springs to open and close valves many millions of times in the life of an engine at the nowadays mileages of several hundreds of thousands of miles without any failure of those springs with a cyclic rate far exceeding those of any spring gun. Race car engines triple the cyclic rate as well as collapse the springs to within .020" of full coil bind at racing rpms of up to 10,000 rpms without failures in a many thousands of miles. ( MY KZ as an example with over 35,000 mile on the clock and routinely twisted to 10K rpms ).
So is the material that is used in a spring for an airgun that much inferior to what is used in the automotive and cycle world. I just don't see that the spring in an air gun being under any more stress than the ones in an engine that cycle far more times than any spring gun ever will in its lifetime.
You read about the high quality materials used in spring gun springs and also the routine breakage of said springs from to heavy a pellets so I am just trying to understand why one spring will last for 20 plus years and millions of cycles and another will last only a couple year and less than maybe 5000 cycles or less.
I have read this entire post but it still does not compute as why air gun springs are so fragile as compared to other springs that are stressed far greater than any air gun spring can ever be in the guns we have today.
Mike
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Airgun springs are not all made in the same factory of the same metal alloy any more than hi-performance engine springs are! The airgun manufacturers want to be able to sell enough of the airguns they produce to earn a profit. The average airgun buyer will likely NOT shoot it enough to exceed the cycle life of the average quality stock spring, so why put the more expensive alloy spring in at the factory?
Even the engines you reference use different types of springs for the different jobs they will be expected to perform. All the different calibers/weights of pellets DO NOT perform at their best on that SAME SPRING that comes stock in all the calibers offered. The valve springs in recip engines ARE of much stronger, more resilient steel alloys and tempers than the factory springs in MOST airguns!
There are a VERY FEW makers, worldwide, of HIGH QUALITY springs for use in airguns. The oldest and most well respected innovator/producer in the USA, in this arena since the '80s, is James Maccari of ARH. A coupla others have been trying for decades, and still are, to catch up!
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Airgun springs are not all made in the same factory of the same metal alloy any more than hi-performance engine springs are! The airgun manufacturers want to be able to sell enough of the airguns they produce to earn a profit. The average airgun buyer will likely NOT shoot it enough to exceed the cycle life of the average quality stock spring, so why put the more expensive alloy spring in at the factory?
Even the engines you reference use different types of springs for the different jobs they will be expected to perform. All the different calibers/weights of pellets DO NOT perform at their best on that SAME SPRING that comes stock in all the calibers offered. The valve springs in recip engines ARE of much stronger, more resilient steel alloys and tempers than the factory springs in MOST airguns!
There are a VERY FEW makers, worldwide, of HIGH QUALITY springs for use in airguns. The oldest and most well respected innovator/producer in the USA, in this arena since the '80s, is James Maccari of ARH. A coupla others have been trying for decades, and still are, to catch up!
Terry
All that is understood and agreed that the airgun makers do not use the very best springs possible since we are talking about a 1000.00 dollar gun compared to a 20,000.00 and up vehicle. Agreed they need to make a profit and not all springs are created equal. I guess I am just set in my ways in that being a mechanic for 45 years working flat rate I had to fix it right the first time and get paid the first time because if it was not right and it came back I did not get paid the second time so I just expect the same from other companies and individuals, silly me as it will never happen is this day and age which is why I buy and rebuild old guns and vehicles that were built when people and companies still had PRIDE in their work and products.
True that all caliber/weight pellets do not perform at their best in all caliber spring guns so why use the same spring in all calibers. Engines come in all levels of quality as well so the spring in them are of vary grades as well yet the failure rate per unit sold is far less that the average spring gun as stated in this post.
It is a shame there are so few makers of very high quality spring for air guns indeed and ARH is definitely one of them as well as Vortek.
What I would like to see is a beehive spring for an air gun made since they have proven to be far superior to conventional straight wound springs in high performance engines, I bet they would perform equally as well in an air gun if not far superior to what is offered now.
I know I would be willing to pay more for a higher quality spring.
Mike
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Designs using gas rams were an effort to improve on the coil springs.
I personally prefer the gas rams, but may be in the minority.
.
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Sorry about the detour-but valve springs-undergo perhaps 1 BILLION cycles-and now a days RARELY break.
From what I have read the reason air guns springs- break-
in what would seem to be a MUCH MILDER environment( valve springs are violently "cocked" many many times per second-
But the claim is the Air gun springs break because they are compressed to ALMOST full compression-
Guessing you have to UNWIND THE WIRE-
say 40 coils- 25mm=80mm circumference per coil- each 80mm coil in a 80mm stroke gun-bent 2mm for 80mm 1mm per 40mm(oh-I was unclear-just uncoiling one coil-circumference)
a carspring-maybe 35MM=110mm circumference each-perhaps 15 coils?? 7.5mm "stroke" so perhaps .5mm per 110mm length- 1mm per 220mm
so the explanation-the air gun springs are BENT MORE- yeah looks like MUCH more 5x as much 220/40=5.5x as much
Looks crude guess like air gun springs are bent 5 times as much as car/motorcycle valve springs-
so makes sense-they break
but like Mike Bulldog says-not so clear WHY heavy pellets are more likely to break the SPRING
On the other hand-as Mike will confirm-CAR/PLANE/MOTORCYCLE valve spring DID break when high performance folks went to BIGGER/HEAVIER VALVES- it was a HUGE problem-
AND it is the original WHY of 4 valve heads instead of 2 valve heads
It wasn't to increase flow-it was because the heavier BIG valves BROKE the valve springs-
as Mikes Kawa -and harley-and GM/CHEVY pushrod V-8 clear demonstrate-you can flow PLENTY of air thru 1 big hole
So there IS car/mc engine indications that HEAVY is tricky
Saying that I STILL am not clear why a 18 grain 22 would be worse than the 13 grain-since the SPRING is THE SAME SPRING- same wire same compression-same everything
WITH the heavy pellet-the spring should slam forward-more slowly??
So I still dont see WHY the heavy pellet is harder-same compression same thickness of wire-
only difference is how it slams forward-and seems like it would slam forward MORE SLOWLY??
Hector says heavy does break springs-but still not clear WHY
I believe him- he is very experienced- but WHY?
PS The numbers-on the springs-guesses-made up numbers off top of head-but they are ballpark-and 5 times the bending-clearly shows why the air gun springs break-
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Why would a beehive spring be better? And what IS a beehive spring anyway?
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Interesting, I have a 177 pro compact. I shot, exclusively, JSB 10.3 gr pellets. They were, by far, the most accurate in my rifle.
(http://i1030.photobucket.com/albums/y364/Thiggs1/Diana%2034%20facelift/image_zps2xeq0x3m.jpeg)
I only got about 2000 rounds on the factory spring. I took it out to shoot after it had been sitting idle for several months. The first shot sounded horably wrong so I stopped immediately. On inspection, my spring was broken in two places. Very odd to me! My question is, if heavy pellets can cause abnormal spring wear via bounce/vacuum, wouldn't this be a perpetual problem for the same rifle in .22 caliber since it would have the same spring, piston, and tube but would always be pushing more weight?
Here is a pic of original spring next to vortek replacement.
(http://i1030.photobucket.com/albums/y364/Thiggs1/Diana%2034%20facelift/image_zpsldx2vppg.jpeg)
Very odd to you, but not to me, T Higgs.
This is EXACTLY what the mathematical models predict.
The two places where there are most collisions between coils when using a loose guide are the beginning and the end. A collision is not the problem, the problem is that when a spring collides with its neighbour coil, it means that while one coil is compressing, the other is decompressing. It is these SWINGS in the DIRECTION of the stress that fatigue the metal much faster than the simple valve operation of motor engines.
When the same gun operates in 0.22" cal. it operates at a much slower rate (the lower MV comes from a slower cycle all over), this reduces the overall bounceback energy, as the expansion ratio of the barrel is greater and the backpressure, therefore, is lower.
The fact that your gun was a compact then tells us that collisions still exist at that barrel length in that caliber, in other words, the 34 Compact is not compact enough in 0.177" cal.
Nice stock, BTW! Congrats!
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Sorry about getting sidetrack with bikes.
Back to heavy pellets in spring guns, but also related to engines since they also use springs to open and close valves. I am somewhat baffled and perplexed how the weight of the pellet has any real impact on the life of a spring and how leaving one cocked for long term degrades the spring by significant amounts.
The spring does not know what weight pellet is in the barrel since it will expand at a given rate allowed by its wire diameter and ID/OD and number of coils and amount of compression when cocked. As T-Higgs stated there are many spring guns that use the same spring, piston, guides and so on for 177, 22, 25 calibers in which you a wide variance in pellet weights per caliber of gun.
In relation a motor vehicle engine uses coil springs to open and close valves many millions of times in the life of an engine at the nowadays mileages of several hundreds of thousands of miles without any failure of those springs with a cyclic rate far exceeding those of any spring gun. Race car engines triple the cyclic rate as well as collapse the springs to within .020" of full coil bind at racing rpms of up to 10,000 rpms without failures in a many thousands of miles. ( MY KZ as an example with over 35,000 mile on the clock and routinely twisted to 10K rpms ).
So is the material that is used in a spring for an airgun that much inferior to what is used in the automotive and cycle world. I just don't see that the spring in an air gun being under any more stress than the ones in an engine that cycle far more times than any spring gun ever will in its lifetime.
You read about the high quality materials used in spring gun springs and also the routine breakage of said springs from to heavy a pellets so I am just trying to understand why one spring will last for 20 plus years and millions of cycles and another will last only a couple year and less than maybe 5000 cycles or less.
I have read this entire post but it still does not compute as why air gun springs are so fragile as compared to other springs that are stressed far greater than any air gun spring can ever be in the guns we have today.
Mike
Thank you Mike, though I should say, before we return to airguns that back in the days (a LONG time ago) I always favoured Ducati engines. I am sure you now know why.
Anyway, coming back to the subject:
The only things in common between motor valve springs and airgun springs is the material they are made from (yes they are made from extremely similar steels), and the fact that they are both coiled. Beyond those two factors there is NOTHING in common.
You are knowledgeable as far as valves and springs are concerned, so let me ask you a few questions and we can then proceed with the subject:
1.- What is the slenderness ratio (length divided by outside diameter) of a motor valve spring? And of an airgun spring?
2.- What is the weight of a valve? And of an airgun piston?
3.- What is the weight of a valve spring and of an airgun spring?
4.- What is the ratio of ID to wire gauge/diameter in a valve spring? and in an airgun spring?
The answer to why valve springs behave completely different from airgun springs is in the proportion of all the dimensions above.
I will await your answers.
Keep well and shoot straight!
Héctor
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Sorry about getting sidetrack with bikes.
Back to heavy pellets in spring guns, but also related to engines since they also use springs to open and close valves. I am somewhat baffled and perplexed how the weight of the pellet has any real impact on the life of a spring and how leaving one cocked for long term degrades the spring by significant amounts.
The spring does not know what weight pellet is in the barrel since it will expand at a given rate allowed by its wire diameter and ID/OD and number of coils and amount of compression when cocked. As T-Higgs stated there are many spring guns that use the same spring, piston, guides and so on for 177, 22, 25 calibers in which you a wide variance in pellet weights per caliber of gun.
In relation a motor vehicle engine uses coil springs to open and close valves many millions of times in the life of an engine at the nowadays mileages of several hundreds of thousands of miles without any failure of those springs with a cyclic rate far exceeding those of any spring gun. Race car engines triple the cyclic rate as well as collapse the springs to within .020" of full coil bind at racing rpms of up to 10,000 rpms without failures in a many thousands of miles. ( MY KZ as an example with over 35,000 mile on the clock and routinely twisted to 10K rpms ).
So is the material that is used in a spring for an airgun that much inferior to what is used in the automotive and cycle world. I just don't see that the spring in an air gun being under any more stress than the ones in an engine that cycle far more times than any spring gun ever will in its lifetime.
You read about the high quality materials used in spring gun springs and also the routine breakage of said springs from to heavy a pellets so I am just trying to understand why one spring will last for 20 plus years and millions of cycles and another will last only a couple year and less than maybe 5000 cycles or less.
I have read this entire post but it still does not compute as why air gun springs are so fragile as compared to other springs that are stressed far greater than any air gun spring can ever be in the guns we have today.
Mike
Thank you Mike, though I should say, before we return to airguns that back in the days (a LONG time ago) I always favoured Ducati engines. I am sure you now know why.
Anyway, coming back to the subject:
The only things in common between motor valve springs and airgun springs is the material they are made from (yes they are made from extremely similar steels), and the fact that they are both coiled. Beyond those two factors there is NOTHING in common.
You are knowledgeable as far as valves and springs are concerned, so let me ask you a few questions and we can then proceed with the subject:
1.- What is the slenderness ratio (length divided by outside diameter) of a motor valve spring? And of an airgun spring?
2.- What is the weight of a valve? And of an airgun piston?
3.- What is the weight of a valve spring and of an airgun spring?
4.- What is the ratio of ID to wire gauge/diameter in a valve spring? and in an airgun spring?
The answer to why valve springs behave completely different from airgun springs is in the proportion of all the dimensions above.
I will await your answers.
Keep well and shoot straight!
Héctor
Hector
Yes fully understand why you prefer Ducatis since they employ Desmodronic valve operation that use no springs at all and are a positive open/close system.
1. Don't have direct numbers for the ratio ( slenderness ) of a particular engines valve springs but only to say they are generally a larger ID/OD and much much shorter than an air gun spring IE. say 1 inch ID x 1.300" OD with a .150" wire diameter and 3 inches long as an example, Although newer engines with four and five valves per cylinder are much closer in size to air gun spring if not the same size only shorter since they are controlling much smaller and lighter valves. Air gun spring are from say .560" ID x .790" OD with a wire size of .105' and 31 coils for one of the smaller size springs as an example ( My FWB 300S Maccarri artic single spring ) and up from there.
2. Engine valve weights from max of possibly 8 ounces or so ( I have never weighed any to be truthful ) to as light as 2 ounces for a five valve engine system, air gun piston likely from 1 pound up to 2 or more pounds as I have never weighed them either.
3. Engine valve springs weigh possibly 8 ounces or less again depending on 2 or more valve style heads and never weighed either, Air gun springs from 8 ounces and up to over a pound again just a estimate.
4. Engine spring ID to wire diameter in a two valve engine IE. ID of .750' to 1.250' and wire diameter of .125" to .200' , four or five valve engine close if not the same as an air gun spring if not even smaller as I have seen springs in newer inline 4 cylinder four valve bike engines with spring of .400" ID and wire diameter of .075" being the norm, Air gun spring again as an example my 300 artic spring of .560' ID and .105" wire diameter.
I understand that air gun springs will in fact behave different due to the much increased length over valve springs but the fact that both are subjected to the same harmonics and loads with engine in my opinion being stressed far more than an air gun ever will. Example as in my 76 Harley shovelhead that I have built from the ground up I am opening the valve to .540" with only .060" from full coil bind at rpms of 6000 max and have 40,000 miles on it with no failures and then my Kawi that has .425" valve lift and is .030" from full coil bind and turns to 10,000 rpm routinely with 35,000 miles on it.
Don't quite understand your comment about coils slamming into each other when gun is fired since the spring is expanding all the coils at the same rate is it not so there should be no reason for the coils to touch if the spring is a good fit on the guides, can understand if a loose fit on guides since spring would be expanding and flailing everywhere inside the spring tube.
I guess its what makes up the so called difference of a cheap spring gun and a high end one although the high end ones really don't seem to be much if any better at designing and producing a good fitting spring guide as compared to the cheap one, at least not the one I have built ( D48, FWB 124,300, B40/TX versus Crosman vantage/Quest guns ) IMO.
A beehive spring has been in use in high performance engines for 10 or so years and is one that has its coils formed in an gradual decreasing diameter at one end in order to help control harmonics and spring fracturing from the rapid vibrations encountered in high revving engine with extreme valve lifts and durations. Harleys have been using beehive springs now since 07 in all big twins.
Mike
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Sorry Hector and phoebeisis the Desmo valves had their time but just to breakdown prone and like a solid lifter cam needed constant adjustment if you hammered on it (racing). the positive valve closure allowed more rpm though...
The Ducati killer was the Gixxer and the reason for multi valves was not broken springs it was because like the Desmodromic valve the lighter the valve the higher the rpm you could hit before inertia caused valve float... the other benefit is smaller valves cool quicker...
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And then came the 5 valve Fizzer. I think they called that the Genesis? 750s were fast, but a buddy had one of the first 1000's and that thing had a powerband a mile wide. I can't think of the name of it, but he had one of those headers with the plates on the end like they put on race boats when they want to keep the noise down.
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Is a fizzer a new ag or alternate mb engine?
We seem to be off track again.
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Not me this time
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Airgun springs are not all made in the same factory of the same metal alloy any more than hi-performance engine springs are! The airgun manufacturers want to be able to sell enough of the airguns they produce to earn a profit. The average airgun buyer will likely NOT shoot it enough to exceed the cycle life of the average quality stock spring, so why put the more expensive alloy spring in at the factory?
Even the engines you reference use different types of springs for the different jobs they will be expected to perform. All the different calibers/weights of pellets DO NOT perform at their best on that SAME SPRING that comes stock in all the calibers offered. The valve springs in recip engines ARE of much stronger, more resilient steel alloys and tempers than the factory springs in MOST airguns!
There are a VERY FEW makers, worldwide, of HIGH QUALITY springs for use in airguns. The oldest and most well respected innovator/producer in the USA, in this arena since the '80s, is James Maccari of ARH. A coupla others have been trying for decades, and still are, to catch up!
You are MOSTLY right, Terry!
Upwards of 90% of all airguns sold are never really used. Most are used for a day or two and then relegated to a closet for years. So, there is no incentive in producing quality springs for airguns that do not need them.
The real difference however between OEM springs and after market replacement springs is not the material, but the heat treatment and post-heat-treatment. Very few OEM springs are steel shot peened, or stress relieved, or set in a proper setting jig. These three things make a lot of difference in the expected life and performance of a spring. IMHO, the "Set Spring" charge that ARH makes for setting of their non-kit springs is probably the best two bucks you can spend.
The other thing is that manufacturers sell on the speed argument, a highly strung gun that yields 1,200 fps for a few weekends sells better than a finely tuned 875 fps gun that will keep its performance for life.
Where you are not completely right is when you say that engine valve springs are made of "stronger, more resilient, steel alloys"; the truth is that ordinary valve spring (as used by Mercedes Benz, Audi, Chrysler, or GM) would last less than the worst OEM spring in an airgun. The steels are VERY similar, but airgun spring makers use different trace materials to increase the resistance of THEIR springs to fatigue and, therefore, breakage. I am not at liberty to discuss who uses what, but I can tell you that 0.1% of copper content in a steel will make the difference between a great airgun spring and a mediocre airgun spring. Same can be said for other trace materials like Silicon, Vanadium, Indium, Tungsten, Nickel, Chromium, Niobium, Aluminum, Sulphur, Titanium and Cobalt.
Jim Maccari (US) makes VERY good springs, so does Tom Gore (Vortek-US), and Titan (UK) lately has been doing very interesting stuff. There are other spring makers, like Venom, but the first three are the ones that are accessible to most shooters. We should be happy we have here in the US two dedicated spring manufacturers.
The material science of the spring would tend to point out in the direction of the "coextruded" bimetallic wire as the solution to most of out complaints, and there is technology to make at least laminated spring ribbon within economical parameters, the use of three different steels in a square section spring could solve the reduction in power over time, the fatigue and the breakage of airgun springs, the question is whether we will ever pay for it.
Keep well and shoot straight
Héctor Medina
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What I would like to see is a beehive spring for an air gun made since they have proven to be far superior to conventional straight wound springs in high performance engines, I bet they would perform equally as well in an air gun if not far superior to what is offered now.
I know I would be willing to pay more for a higher quality spring.
Mike
Mike;
I also thought that conical springs could help in the equation, specially if we were to assemble a series of conical elements to make for the whole length of the airgun mainspring. To this day I have not found someone willing to try the idea. Some extremely high quality Match guns of the past have used TWO springs instead of one (counterwound, so as to eliminate the distension torque on the gun), that also brought life cycles in the region of hundred of thousands of shots. So, there is merit in that idea, again, no one of the three manufacturers I have talked to has taken the idea.
For those that are wondering what is a beehive spring, here is a comparison of normal and beehive springs:
(http://speednik.com/files/2012/04/MCP-0207-myth-2.jpg)
Another interesting spring technology is the "wave" spring, but when I talked to Smalley:
http://www.smalley.com/about-smalley-wave-springs (http://www.smalley.com/about-smalley-wave-springs)
At first they seemed VERY interested in making wave springs for airguns. As soon as I sent them real parameters of operation, they elegantly declined.
In this particular instance, it is the slenderness ratio what would wreck a wave spring from functioning inside an airgun, even if VERY closely guided inside and out.
There are other avenues that could point to the long range development of the airgun mainspring but, I am afraid that given the average value of the spring and the number of cycles it lives, manufacturers are better served by making medium good springs that will get replaced every 10,000 to 15,000 shots than making the "perfect" spring where they can only hope to sell ONE spring during the lifetime of the shooter.
Hope I am making sense.
Hector
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Designs using gas rams were an effort to improve on the coil springs.
I personally prefer the gas rams, but may be in the minority.
.
Kim;
Gas Struts/Springs (non adjustable) and Gas Rams (adjustable) have been, up to now, a technology in progress. From the air filled Menaldi in Argentina, then the Theoben that copied the principle, then the Nitro Pistons and Vortek units, they have been inefficient (you need to use 45# of cocking force to get 18 ft-lbs back at the muzzle), unreliable (I once went to a Match with a gas strutted rifle, placed at the top of the pack the first day only to discover that the strut had leaked overnight and that I had no operable gun for the second day of the Match), impossible to repair (once a strut leaks, you have to throw it away, and if it is a ram, the process of setting up the fill pressure is so complicated that you need to do it standing next to a Chrono).
I have faith in the technology for the future and I am in fact awaiting a set of N-Tec piston and trigger units to test on a Diana 54, we'll see when the technology really matures and starts offering what simple steel coil springs offer.
;)
Will keep you all posted.
Hector
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I scrolled thru this posting and didn't see anything regarding what I consider to be an important factor in spring life: wire diameter and metallurgy. Both JM and I have tested various springs and found that if your wire dia is less than .126" and the metal is music wire; heavy pellets can shorten spring life. If the wire is above .126" diameter, the spring will handle heavier pellets better.
R-9/HW95,98, 50S, 77,97 all use .122" music wire. Early 77's used 3mm (.118). FWB 124 used 3mm also. R7/HW30 was under .110" but I don't recall the exact diameter. Many older spanish guns (up to mid 2000s) used 3mm(.118)..Gamo and Norica for sure.
Diana magnums have used .126-.128 music wire and they were seriously hardened for added stiffness. This also made them brittle and subject to failure, even though they were heavier wire.
Air Arms TX and PS use .128" wire. Several UK Webley models used .128" wire, as has BSA. The Webley Patriot/Kodiaks had .140+" wire, as did the AA Pro Elite.
R-1/HW80 uses .135: or better wire.
Now- where does pellet weight come in? For .177's with sub .126 wire, keep your pellets between 7.9 and 9.5 gr for optimum spring life. For .22 with sub .126" wire, stay between 12-16.5 gr. Guns with heavier wire can handle heavier pellets with little ill effect. Springs that are higher grade than music wire, such as are made with high chrome and silicon (not silicone!) content can be tougher and longer lasting. I know this is the metallurgy JM at ARH preferred.
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I scrolled thru this posting and didn't see anything regarding what I consider to be an important factor in spring life: wire diameter and metallurgy.
Yeah, um, they have been talking about that throught the last forty posts or so... Maybe scrolling is not the same as actually reading?
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Sorry about the detour-but valve springs-undergo perhaps 1 BILLION cycles-and now a days RARELY break.
From what I have read the reason air guns springs- break-
in what would seem to be a MUCH MILDER environment( valve springs are violently "cocked" many many times per second-
But the claim is the Air gun springs break because they are compressed to ALMOST full compression-
Guessing you have to UNWIND THE WIRE-
say 40 coils- 25mm=80mm circumference per coil- each 80mm coil in a 80mm stroke gun-bent 2mm for 80mm 1mm per 40mm(oh-I was unclear-just uncoiling one coil-circumference)
a carspring-maybe 35MM=110mm circumference each-perhaps 15 coils?? 7.5mm "stroke" so perhaps .5mm per 110mm length- 1mm per 220mm
so the explanation-the air gun springs are BENT MORE- yeah looks like MUCH more 5x as much 220/40=5.5x as much
Looks crude guess like air gun springs are bent 5 times as much as car/motorcycle valve springs-
so makes sense-they break
but like Mike Bulldog says-not so clear WHY heavy pellets are more likely to break the SPRING
On the other hand-as Mike will confirm-CAR/PLANE/MOTORCYCLE valve spring DID break when high performance folks went to BIGGER/HEAVIER VALVES- it was a HUGE problem-
AND it is the original WHY of 4 valve heads instead of 2 valve heads
It wasn't to increase flow-it was because the heavier BIG valves BROKE the valve springs-
as Mikes Kawa -and harley-and GM/CHEVY pushrod V-8 clear demonstrate-you can flow PLENTY of air thru 1 big hole
So there IS car/mc engine indications that HEAVY is tricky
Saying that I STILL am not clear why a 18 grain 22 would be worse than the 13 grain-since the SPRING is THE SAME SPRING- same wire same compression-same everything
WITH the heavy pellet-the spring should slam forward-more slowly??
So I still dont see WHY the heavy pellet is harder-same compression same thickness of wire-
only difference is how it slams forward-and seems like it would slam forward MORE SLOWLY??
Hector says heavy does break springs-but still not clear WHY
I believe him- he is very experienced- but WHY?
PS The numbers-on the springs-guesses-made up numbers off top of head-but they are ballpark-and 5 times the bending-clearly shows why the air gun springs break-
WOW!
EXCELLENT ANALYSIS, Phoebeisis!
Yes, the airgun mainspring STARTS more stressed than any motor valve spring. That is the "intrinsic stress" (not always relieved completely), then you add the preload (sometimes we preload our mainsprings by a good 2" this is the "static stress", then you add the compression ratio by taking an 11.75" spring and compressing it to within ½" of solid and then releasing it in one go, this is the "dynamic stress". IF you compress a spring that has a 7.5 mm's stroke to within 1 mm of solid, you are compressing it 87% of its available length, the airgun mainspring is compressed 95% of its available length, does not seem like much until you invert the numbers: CLEARANCE for the engine valve spring is 2½ times (roughly) what it is for the airgun mainspring.
Now, the whole thing goes back to the bounceback of the piston.
If you can picture a relatively long spring that is distending, you can also picture the "longitudinal wave" that the bounceback will create.
Look at this video from minute 1:00
https://www.youtube.com/watch?v=GIkeGBXqWW0 (https://www.youtube.com/watch?v=GIkeGBXqWW0)
Now, the slinky is a weak and long spring, but look how the piece of thread goes back after being moved when the longitudinal wave hits the end and bounces back, but the maths tell us that in loosely guided airgun mainsprings happens exactly the same thing:
(https://imagizer.imageshack.us/v2/1024x557q90/923/wZCAIi.jpg)
Look at how at milisecond 27 onwards there are NEGATIVE compression ratios, which means that while one coil is distending the next coil is compressing, this is where there are collisions, but the collisions, again, are not the important part, those are a symptom. What REALLY matters is that the stress excursion in a coil goes from positive to negative and positive again, this is equivalent to 3 duty cycles PER BOUNCEBACK.
And if this was a rifle with no guide or with a very loose guide, then there could be up to three bouncebacks, therefore, up to 9 duty cycles per shot.
And it is in THIS last number where the difference between a heavy pellet and a light one makes a huge difference: With a heavy pellet, the mass of the pellet and its resistance to movement create a larger backpressure that in turn is the main "engine" behind the bounceback(s).
It would be interesting to see an XRay of one of those valve springs that broke with heavy valves and compare it to a broken airgun mainspring, I would tend to think that the fractures would be quite similar.
Keep well and shoot straight!
Hector
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In a word: Oscillation. Seems like we want to minimize that as much as possible.
Yeah?
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I knew you would get around to the second paper eventually ...
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Yes fully understand why you prefer Ducatis since they employ Desmodronic valve operation that use no springs at all and are a positive open/close system.
1. Don't have direct numbers for the ratio ( slenderness ) of a particular engines valve springs but only to say they are generally a larger ID/OD and much much shorter than an air gun spring IE. say 1 inch ID x 1.300" OD with a .150" wire diameter and 3 inches long as an example, Although newer engines with four and five valves per cylinder are much closer in size to air gun spring if not the same size only shorter since they are controlling much smaller and lighter valves. Air gun spring are from say .560" ID x .790" OD with a wire size of .105' and 31 coils for one of the smaller size springs as an example ( My FWB 300S Maccarri artic single spring ) and up from there.
2. Engine valve weights from max of possibly 8 ounces or so ( I have never weighed any to be truthful ) to as light as 2 ounces for a five valve engine system, air gun piston likely from 1 pound up to 2 or more pounds as I have never weighed them either.
3. Engine valve springs weigh possibly 8 ounces or less again depending on 2 or more valve style heads and never weighed either, Air gun springs from 8 ounces and up to over a pound again just a estimate.
4. Engine spring ID to wire diameter in a two valve engine IE. ID of .750' to 1.250' and wire diameter of .125" to .200' , four or five valve engine close if not the same as an air gun spring if not even smaller as I have seen springs in newer inline 4 cylinder four valve bike engines with spring of .400" ID and wire diameter of .075" being the norm, Air gun spring again as an example my 300 artic spring of .560' ID and .105" wire diameter.
I understand that air gun springs will in fact behave different due to the much increased length over valve springs but the fact that both are subjected to the same harmonics and loads with engine in my opinion being stressed far more than an air gun ever will. Example as in my 76 Harley shovelhead that I have built from the ground up I am opening the valve to .540" with only .060" from full coil bind at rpms of 6000 max and have 40,000 miles on it with no failures and then my Kawi that has .425" valve lift and is .030" from full coil bind and turns to 10,000 rpm routinely with 35,000 miles on it.
Don't quite understand your comment about coils slamming into each other when gun is fired since the spring is expanding all the coils at the same rate is it not so there should be no reason for the coils to touch if the spring is a good fit on the guides, can understand if a loose fit on guides since spring would be expanding and flailing everywhere inside the spring tube.
I guess its what makes up the so called difference of a cheap spring gun and a high end one although the high end ones really don't seem to be much if any better at designing and producing a good fitting spring guide as compared to the cheap one, at least not the one I have built ( D48, FWB 124,300, B40/TX versus Crosman vantage/Quest guns ) IMO.
A beehive spring has been in use in high performance engines for 10 or so years and is one that has its coils formed in an gradual decreasing diameter at one end in order to help control harmonics and spring fracturing from the rapid vibrations encountered in high revving engine with extreme valve lifts and durations. Harleys have been using beehive springs now since 07 in all big twins.
Mike
Thanks, Mike! Just a note, I PREFERRED Ducatis, that was 44 years ago, good memories, but long gone and no interest in getting them back.
Great data and I am very glad that you humoured me, thanks again!
Yes, you are absolutely right, the main difference is in the length; and length brings mass/weight and the chance for a longitudinal wave to settle itself into the operation cycle. Without the length (to diameter), there is no way a spring can experience bounce back.
You are also right that the AVERAGE stress in an engine valve spring is higher than in an airgun spring, BUT, all the stresses in the valve springs go in the same direction, whereas in the airgun spring the stresses even change signs and, for sections of the spring (the beginning and the end), the stresses go from a positive value to the same value but in the opposite direction.
You are probably aware that the overall stress is the mean (average) stress, plus the stress excursion. It is these extreme stress excursions that increase the overall stress in an airgun mainspring to levels that engine valve springs will never experience.
What you refer as the loose guide case is only a matter of degree. Even the tightest guides cannot completely eliminate the longitudinal waves that can settle into long (and unguided for half of their lengths) airgun mainsprings. Here we come to an interesting opportunity: To my knowledge, no one has come up with an outside guide that comes from the piston and extends backwards. If someone was to make an "outside" guide that was sort of a huge top-hat, and that would come back from the piston and engage up to the half of the spring that is unsupported by the inside (rear) guide, we MIGHT have found something that is not only interesting, but useful. The rear guide would provide friction and dampening to the rear section of the spring from the inside, but the forward guide would provide support and friction to the spring from the outside.
What I personally find interesting about Beehive springs is not their external geometry, but their (purported?) egg-shaped sectioned wire. The three dimensional analysis of the dynamic spring stresses gets really complicated, but an egg-shaped section clearly minimizes the stresses on the ID of the spring, while maximizing the resistance on the OD of the spring. Can you tell me if what I understand from them is real? (that the section of the wire they use is eggshaped?)
Square sectioned wire has been tried and it has its own problems, the only way I can see of using advantageously square sectioned wire would be to use a three layered steel ribbon to make those springs and that is going to be hard to test or even try.
Few people realize that airguns have more in common with internal combustion engines than with firearms. So this thread has been a lesson to all (me included).
THANKS!
Héctor
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K O Kirby
I was unclear-valve float broke the valve springs-cut from Wiki below-
too much valve
too much acceleration from cam
too little spring
But springs got better-much better-and GMs 5.3 2 valve V-8 easily matches Fords much more complicated 24 valve Twin Turbo V-6- matches it in MPG HP TORQUE -and is cheaper to build-easier to package-
Like Hector suggests-I wouldn't be surprised to find out that they-valve springs- broke for much the same reason that air gun springs break-some sort of oddball vibration related to the two waves coming together and constructively interfering with one another-effectively increasing the BENDING of the wire Just at that point-
This is what the Hector's figure 8 might indicate-both ends -rebound -at different times-and compress MORE that the actual cocking compression
The more compression-means more wire bending on rebound-at end segments- than when cocked
more bending means more likely to break-eventually
The slinky video-cool-love them-good teaching toy-and fun!!
WIKI cut below
i]Valve float is an adverse condition which can occur at high engine speeds when the poppet valves in an internal combustion engine valvetrain do not properly follow the closure phase of the cam lobe profile. This reduces engine efficiency and performance and potentially increases engine emissions. There is also a significant risk of severe engine damage due to valve spring damage and/or pistons contacting the valves.[/i]
Hector-are heavy pellets less far down the barrel than light pellets when the piston slams down- 9.6/1000 sec in one of those papers?If they are them the "back pressure" would be higher-which would help slam the piston back up
Thanks
Charlie
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I scrolled thru this posting and didn't see anything regarding what I consider to be an important factor in spring life: wire diameter and metallurgy. Both JM and I have tested various springs and found that if your wire dia is less than .126" and the metal is music wire; heavy pellets can shorten spring life. If the wire is above .126" diameter, the spring will handle heavier pellets better.
R-9/HW95,98, 50S, 77,97 all use .122" music wire. Early 77's used 3mm (.118). FWB 124 used 3mm also. R7/HW30 was under .110" but I don't recall the exact diameter. Many older spanish guns (up to mid 2000s) used 3mm(.118)..Gamo and Norica for sure.
Diana magnums have used .126-.128 music wire and they were seriously hardened for added stiffness. This also made them brittle and subject to failure, even though they were heavier wire.
Air Arms TX and PS use .128" wire. Several UK Webley models used .128" wire, as has BSA. The Webley Patriot/Kodiaks had .140+" wire, as did the AA Pro Elite.
R-1/HW80 uses .135: or better wire.
Now- where does pellet weight come in? For .177's with sub .126 wire, keep your pellets between 7.9 and 9.5 gr for optimum spring life. For .22 with sub .126" wire, stay between 12-16.5 gr. Guns with heavier wire can handle heavier pellets with little ill effect. Springs that are higher grade than music wire, such as are made with high chrome and silicon (not silicone!) content can be tougher and longer lasting. I know this is the metallurgy JM at ARH preferred.
Russ;
There have been passing mentions of metallurgy, but yes, there are things we have not discussed basically because this thread has tried to center on the WHY. Not on the how to avoid , what weight is considered heavy or mid, or what policies of operation would reduce the "damage" to the spring (which was the term used by the original poster).
You are right in that there are a number of things we have not explored nor even mentioned (from short stroked airguns to antibounce pistons) but, I repeat, the thread was dedicated to getting to understand the dynamics of the stresses inside an airgun mainspring when the shot was released.
Thanks for your valuable input, I am sure more than a few will take note and take this as one of the important data to be filed away for future reference.
Keep well and shoot straight!
Héctor
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In a word: Oscillation. Seems like we want to minimize that as much as possible.
Yeah?
Yeah!
Problem with a short answer like "oscillations" is that oscillations are present in many devices and they do not break things. It is the peculiar slenderness ratio of the airgun mainspring that creates oscillations that go from one sense to the opposite. And that gets exaggerated with heavy pellets.
But in a nutshell, you are right, reducing the bucking, bouncing and the buzz (the "sproing" and the twang) in an airgun IS desireable. That is why experienced shooters and gunsmiths will always tell you to LISTEN to your airgun.
Thanks!
Héctor
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Hector-are heavy pellets less far down the barrel than light pellets when the piston slams down- 9.6/1000 sec in one of those papers?If they are them the "back pressure" would be higher-which would help slam the piston back up
Thanks
Charlie
That is my understanding, Charlie.
And it all starts from a slower cycle that ends in a lower MV.
Most models yield a result that pellets require pretty much the same energy to get engraved, upset, and started in their trip, but IMHE, heavy pellets are slower FROM THE START, and therefore, they are closer to the breech when the pressure starts building to the point where piston bounce back can occur.
Thanks for your insights!
Hector
-
Thanks, Mike! Just a note, I PREFERRED Ducatis, that was 44 years ago, good memories, but long gone and no interest in getting them back.
Great data and I am very glad that you humoured me, thanks again!
Yes, you are absolutely right, the main difference is in the length; and length brings mass/weight and the chance for a longitudinal wave to settle itself into the operation cycle. Without the length (to diameter), there is no way a spring can experience bounce back.
You are also right that the AVERAGE stress in an engine valve spring is higher than in an airgun spring, BUT, all the stresses in the valve springs go in the same direction, whereas in the airgun spring the stresses even change signs and, for sections of the spring (the beginning and the end), the stresses go from a positive value to the same value but in the opposite direction.
You are probably aware that the overall stress is the mean (average) stress, plus the stress excursion. It is these extreme stress excursions that increase the overall stress in an airgun mainspring to levels that engine valve springs will never experience.
What you refer as the loose guide case is only a matter of degree. Even the tightest guides cannot completely eliminate the longitudinal waves that can settle into long (and unguided for half of their lengths) airgun mainsprings. Here we come to an interesting opportunity: To my knowledge, no one has come up with an outside guide that comes from the piston and extends backwards. If someone was to make an "outside" guide that was sort of a huge top-hat, and that would come back from the piston and engage up to the half of the spring that is unsupported by the inside (rear) guide, we MIGHT have found something that is not only interesting, but useful. The rear guide would provide friction and dampening to the rear section of the spring from the inside, but the forward guide would provide support and friction to the spring from the outside.
What I personally find interesting about Beehive springs is not their external geometry, but their (purported?) egg-shaped sectioned wire. The three dimensional analysis of the dynamic spring stresses gets really complicated, but an egg-shaped section clearly minimizes the stresses on the ID of the spring, while maximizing the resistance on the OD of the spring. Can you tell me if what I understand from them is real? (that the section of the wire they use is eggshaped?)
Square sectioned wire has been tried and it has its own problems, the only way I can see of using advantageously square sectioned wire would be to use a three layered steel ribbon to make those springs and that is going to be hard to test or even try.
Few people realize that airguns have more in common with internal combustion engines than with firearms. So this thread has been a lesson to all (me included).
THANKS!
Hector
Once a biker always a biker even if you don't ride anymore.
Agreed that due to the huge difference in lengths of spring between air guns and engines the stresses are far different and an engines spring likely will never see the bounce back that air gun spring experience except during valve float as mentioned before since when a valve floats the spring has lost all control over the valve and is behaving exactly like one in an air gun that has just been fired and is why they either break or the valve hits the piston if its is what's known as an interference engine ( there is not enough clearance for the valve to be fully open with the piston at top dead center ) hence the valve and piston collide with each other.
Your idea of a piston mounted outer spring guide is indeed intriguing and would likely subdue much if not all of the springs erratic behaviors in the gun when fired, but is the Vortek outer guides that are part of the rear inner guides basically doing the same thing just from the other end of the spring or would a dual outer guide system be even better such as the rear outer Vortek guide as well as an internal piston guide that precisely fits over the outer rear guide so that the spring is contained fully thru its entire firing cycle. That should all but eliminate any bounce back or collision of coils when fired since the spring would unable to move in any direction but longitudinal along the actions tube and guides axis.
The beehive springs that Harley uses are still round wire coils with just a decreasing diameter at one end. Not sure if when you refer to egg shaped wire you mean the actual wire profile as being egg shaped versus round wire like air gun spring are now or just referring to the decreasing diameter of the coils. But if referring to actual egg shaped wire I have never seen such a spring or if I have did not notice the wires profile close enough, but I am certain that Harley beehive springs are a round wire of decreasing diameter.
I know that older GM performance engines such as vette motors and Z28s, GTOs etc used a flat ribbon style inner coil spring that was placed inside the outer round wire coiled valve springs as well as being counter wound to the outer spring to help dampen oscillations at higher rpm as well as control valve float in them so those are not without merit either. Metallurgy has grown by leaps and bounds since then so valve spring breakage in engines has also been significantly reduced since the 60s and 70s.
Yes there are far more similarities between the two style springs than most realize and is why I brought it up as well there are difference also. If we are learning as I know I am then we are making progress even if it only baby steps.
Mike
Héctor
[/quote]
-
Hector-
thanks for your quick answer-so heavier pellets cause more bounce back than lighter pellets-because the pressure in the barrel is higher when the piston slams down- because the barrel volume under the pellets is less with the heavier pellet- so more pressure means more bounce back-
causing more "weird" backward compressions-and this breaks springs probably for the same reason valve float broke springs in the "old days" hence the pretty complicated but pretty cool Ducati solution-
heah-why couldn't air guns "catch" the piston(in a way like ducati) and PREVENT it from bouncing-control its motion-lock it forward?
No wonder one of those papers suggests spring guides to prolong spring life (guessing those guides scrape off-friction-some of the "bad rebound" energy-or at least keep is linear-not much wobble up and down)
A question
1)-does my RWS 460 have a guide??($360 new)-looking at diagram seems to show an inner guide-and hard to tell but maybe the piston is hollow-and acts as an outer guide??
Mike-I still find it hard to believe that 5000 cycle life-when motor valve springs get 1 BILLION- couldn't be "price" solved-
your 40 year old Kawasaki-10,000 RPM- maybe 80 per second(guessing those aren't the OEM springs-or tops-)-
But hector assures us air gun springs are equal in quality to pricy car springs-
and that makes sense since even pricy car springs-pricy brands and fast cars-are CHEAP
5000 cycles vs 1 BILLION- a violent 1 BILLION cycles-all because of a little bounce/float
Hey you guys much have watched that history channel Tacoma Narrows bridge failure-I don't know how much resonance you can get in 20/1000 second-all those back and forth compressions-(but less and less not like Tacoma bridge?)
but 5000 cycles-YIKES!
Never would have guessed 5000 cycles!
-
Charles
Your RWS 460 does have an inner guide of sorts that is likely a fairly loose fit inside the rear of the spring and you are correct in that the piston is hollow where the spring seats at the front of the piston so it acts as a very loose guide as well does the receiver's tube also but the problem is none of those part are a tight enough tolerance to truly control the spring movement to just a longitudinal direction and is why you likely hear some spring twang or buzz when fired.
The reason of why not is money and labor to hand fit every spring and guides to precise fits so that each gun would be blueprinted so to speak. It can be done but then that 360 buck gun would be 8 to 900 bucks not that those are much if any better. I had a friend who bought a FWB sporter new for 900 bucks and when he got it the barrel was bent so bad you could not see the muzzle end when looking thru the breech with the gun cocked. he did not want to send it back so a picnic bench seat 2x4s with the barrel stuck between them and some leverage and it was straight as could be .
Guides are indeed good but no pricey air rifles have guides of the proper diameters to do the correct job required as it is just not cost effective in today market place and I would say Daina ,FWB, HW, and other very high end spring gun makers are pretty much the same in quality of the guides and spring they use as its all about profits and sales.
IMO nothing today is made with the same pride or quality as it was 30 or 40 years ago when we actually cared about what we made and sold and not how much money or profit we could make.
Mike
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Mike- thanks for your answer
so my 460 has guides-but they are too crude/loose to be extremely effective
and Hand fitting-no way
What do German workers make
$40 plus maybe another $20 in benefits- figure another $60-$100 per rifle? for perhaps double the life of a $20 part-that will last years for most folks(hector is right-most air rifles-just sit
You are right -far less hand fitting type care-
not on a mass produced rifle from Germany that delivered cost me just $360-
RWS probably sold it for just $250-or less-
can't do hand fitting on a mass produced product
Having to compete with the "good enough" very cheap labor barely adequate QC guns produced in China
means there aren't many-any-hand fitted firearms
China-and the cheap stuff syndrome-oh well-
but china is riding for a fall-adulterating baby milk-selling FAKE anticoagulants-BIG manufacturers doing this- and their HUGE masses of people being urinated on by their elites-
manufacturing will come home-USA wages are down-and china products are rising in price as their wages rise(to prevent another civil war)-and their managed economy-filled with fake numbers-
Glad I don't live in china-
old chinese curse "may you live in interesting times"
safe bet they are riding for a fall-not unlike Japan in the 1980's
-
Charles
With you 100% and only hope we can hold on till they fall as we are also in that never ending spiral like you see at the malls where you put a coin in the top of a funnel and watch it slowly spiral down into the abyss never to be seen again.
Its a &^^& shoot now just to see who falls first.
Mike
-
Ok after reading all of this , I miss my slinky , muscle cars and widow makers , but will accept the shortened spring life to get the down range energy and accuracy in wind and range using heavier pellets.
I do watch how heavy of pellet I use , one can hear it in the spring when it is pushing its limit.
On an interesting note , I was breaking in a new .177 springer , had about 10 CP 10.5 through it, with fairly little dieseling, grabbed a stray 8 gr polymag, shot it and had a 5 yard vapor trail and sonic/explosive crack. Seems the heavier pellets were reducing the initial amount of break in dieseling. I did try other lighter pellets and had similar results.
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Sounds more like a sonic crack from the pellet breaking the sound barrier to me. I only shoot JSB 10.34s in all my 177s including my 2 FWB 300s that shoot them at 575 fps but are deadly accurate out to 55 yards also with them.
Mike
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Designs using gas rams were an effort to improve on the coil springs.
I personally prefer the gas rams, but may be in the minority.
.
Kim;
Gas Struts/Springs (non adjustable) and Gas Rams (adjustable) have been, up to now, a technology in progress. From the air filled Menaldi in Argentina, then the Theoben that copied the principle, then the Nitro Pistons and Vortek units, they have been inefficient (you need to use 45# of cocking force to get 18 ft-lbs back at the muzzle), unreliable (I once went to a Match with a gas strutted rifle, placed at the top of the pack the first day only to discover that the strut had leaked overnight and that I had no operable gun for the second day of the Match), impossible to repair (once a strut leaks, you have to throw it away, and if it is a ram, the process of setting up the fill pressure is so complicated that you need to do it standing next to a Chrono).
I have faith in the technology for the future and I am in fact awaiting a set of N-Tec piston and trigger units to test on a Diana 54, we'll see when the technology really matures and starts offering what simple steel coil springs offer.
;)
Will keep you all posted.
Hector
Unfortunate that the technology didn't work for you. It works well, and reliably for me, but not that I am a target match shooter.
I find the NP pistons easier to cock in my magnum rifles compared to my similarly rated conventional springs guns. Plus, the pressurized gas is not prone to the same harmonics as mechanical springs, not to mention the twisting and flexing inherent in the coil design.
And the cartridge design makes replacement so much easier for gas rams as compared to coil springs. No need for spring guides or damping tar.
Head to head comparison; I'll choose my Benjamin NP XL over my Hat Pat any day, and even my NP2 over the 350 purely for the ease of shooting cycle. Similar powers, but the rams are lighter, better balanced, and easier to shoot.
My 460 may still be my most accurate shooter out to 30 m, but this probably more due to its general workmanship than its spring. I would love to see a 460 equipped with a gas ram instead of the spring; I can't help but think it would be an even better shooter for reduced twang and noise, and with a smoother shot cycle.
JMHO Your results may vary.
.
-
DOKF/Kim
.
Your icon-WORLDS CUTEST PUPPY!
Bullawg Death Motorcycle club-in BLACK- not remotely cute
BackRoads has a suitable for Faluga sniper looking rifle-
Hector is shooting-veiled warning maybe
Versus World's Cutest Puppy
How could anyone get snarky and disagree with you-NOT FAIR
But I have to agree on the 460-got mine 4 weeks ago-ran one dry swab down the barrel-
and it was more accurate than I can shoot-right out of the box
A question-I ONLY shoot in my hallway- 10 meters if I stand in the front room
It doesn't seem noisy-and I'm old-and sensitive to noise.
Are these air rifles seemingly LOUDER outside??
-
DOKF/Kim
.
Your icon-WORLDS CUTEST PUPPY!
Bullawg Death Motorcycle club-in BLACK- not remotely cute
BackRoads has a suitable for Faluga sniper looking rifle-
Hector is shooting-veiled warning maybe
Versus World's Cutest Puppy
How could anyone get snarky and disagree with you-NOT FAIR
But I have to agree on the 460-got mine 4 weeks ago-ran one dry swab down the barrel-
and it was more accurate than I can shoot-right out of the box
A question-I ONLY shoot in my hallway- 10 meters if I stand in the front room
It doesn't seem noisy-and I'm old-and sensitive to noise.
Are these air rifles seemingly LOUDER outside??
Charles
You ever see the movie Harley- Davidson and the Marlboro Man with Don Johnson and Mickey Rourke, well the bike that Don Johnson rode was made by the now defunct bike builders with that logo and it was a 1994 Harley FXR with that exact logo painted on a raw steel tank. the FXR was the best handling bike Harley ever made not that they made any good handling bikes.
It has to do with my other motto of never ride faster than your angels can fly since I have had many incidents on dirt and street bikes that if my angels were not with me I would not still be here so it has significance to me.
Mike
-
Designs using gas rams were an effort to improve on the coil springs.
I personally prefer the gas rams, but may be in the minority.
.
Kim;
Gas Struts/Springs (non adjustable) and Gas Rams (adjustable) have been, up to now, a technology in progress. From the air filled Menaldi in Argentina, then the Theoben that copied the principle, then the Nitro Pistons and Vortek units, they have been inefficient (you need to use 45# of cocking force to get 18 ft-lbs back at the muzzle), unreliable (I once went to a Match with a gas strutted rifle, placed at the top of the pack the first day only to discover that the strut had leaked overnight and that I had no operable gun for the second day of the Match), impossible to repair (once a strut leaks, you have to throw it away, and if it is a ram, the process of setting up the fill pressure is so complicated that you need to do it standing next to a Chrono).
I have faith in the technology for the future and I am in fact awaiting a set of N-Tec piston and trigger units to test on a Diana 54, we'll see when the technology really matures and starts offering what simple steel coil springs offer.
;)
Will keep you all posted.
Hector
Unfortunate that the technology didn't work for you. It works well, and reliably for me, but not that I am a target match shooter.
I find the NP pistons easier to cock in my magnum rifles compared to my similarly rated conventional springs guns. Plus, the pressurized gas is not prone to the same harmonics as mechanical springs, not to mention the twisting and flexing inherent in the coil design.
And the cartridge design makes replacement so much easier for gas rams as compared to coil springs. No need for spring guides or damping tar.
Head to head comparison; I'll choose my Benjamin NP XL over my Hat Pat any day, and even my NP2 over the 350 purely for the ease of shooting cycle. Similar powers, but the rams are lighter, better balanced, and easier to shoot.
My 460 may still be my most accurate shooter out to 30 m, but this probably more due to its general workmanship than its spring. I would love to see a 460 equipped with a gas ram instead of the spring; I can't help but think it would be an even better shooter for reduced twang and noise, and with a smoother shot cycle.
JMHO Your results may vary.
.
Kim
Do you know that Hatsan Vortex rams are actually a recreation of the old Theoben ram in that they can be depressurized and are filled with HPA air not nitrogen or other inert gases. You use the same fill fitting probe that you use to fill their PCP guns so they have a release screw and a fill port and the one I have that will eventually find its way into a B-19 clone called a Firepower FP-1 states on the side of it to not exceed 125 BAR pressure, but my point is that the pressure in them can be fine tuned to each person needs and desires.
Mike
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Charles,
My springers (HatPat, 350, 460) are all noticeably loud for my neighbours, thus too loud. My NPXL, NV, and NP2 rifles are all much quieter, and don't seem to draw attention from the neighbours.
I am trying hard to avoid the fate of another member who ran afoul of the neighbours ...
I don't think they are any louder outside, but hard for me to compare as it displeases the wife when I shoot indoors. ;-(
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Mike,
My Hat Pat is a traditional spring, not a ram. It might be worth a try to put a ram in it; could tame the beast without losing too much useful power.
In the meantime, I just use it out in the country far from prying ears. Still fun to play with.
.
-
Hector
Once a biker always a biker even if you don't ride anymore.
Agreed that due to the huge difference in lengths of spring between air guns and engines the stresses are far different and an engines spring likely will never see the bounce back that air gun spring experience except during valve float as mentioned before since when a valve floats the spring has lost all control over the valve and is behaving exactly like one in an air gun that has just been fired and is why they either break or the valve hits the piston if its is what's known as an interference engine ( there is not enough clearance for the valve to be fully open with the piston at top dead center ) hence the valve and piston collide with each other.
Your idea of a piston mounted outer spring guide is indeed intriguing and would likely subdue much if not all of the springs erratic behaviors in the gun when fired, but is the Vortek outer guides that are part of the rear inner guides basically doing the same thing just from the other end of the spring or would a dual outer guide system be even better such as the rear outer Vortek guide as well as an internal piston guide that precisely fits over the outer rear guide so that the spring is contained fully thru its entire firing cycle. That should all but eliminate any bounce back or collision of coils when fired since the spring would unable to move in any direction but longitudinal along the actions tube and guides axis.
The beehive springs that Harley uses are still round wire coils with just a decreasing diameter at one end. Not sure if when you refer to egg shaped wire you mean the actual wire profile as being egg shaped versus round wire like air gun spring are now or just referring to the decreasing diameter of the coils. But if referring to actual egg shaped wire I have never seen such a spring or if I have did not notice the wires profile close enough, but I am certain that Harley beehive springs are a round wire of decreasing diameter.
I know that older GM performance engines such as vette motors and Z28s, GTOs etc used a flat ribbon style inner coil spring that was placed inside the outer round wire coiled valve springs as well as being counter wound to the outer spring to help dampen oscillations at higher rpm as well as control valve float in them so those are not without merit either. Metallurgy has grown by leaps and bounds since then so valve spring breakage in engines has also been significantly reduced since the 60s and 70s.
Yes there are far more similarities between the two style springs than most realize and is why I brought it up as well there are difference also. If we are learning as I know I am then we are making progress even if it only baby steps.
Mike
Thanks, Mike!
The current Vortek PG-2 systems use an inner guide (very normal), and an outer guide (so far, only Vortek uses it). BUT they are both at the rear, as you know.
What I am envisioning is a system that would "encase" the spring. On the inside from the rear, and on the outside from the front. MOST systems nowadays use a TopHat (an inheritance of the die and stamping industry). But if the TopHat was extended backwards to surround the spring, we could have a system that is not piston mounted (you do not really want to alter the weight of the piston), but that works as BOTH the TopHat AND the outside guide.
In the common systems, the fore section of the spring is completely unsupported, both on the inside and on the outside and, while this will prevent the breakage of the rear section of the spring (most common), it will not prevent all the havoc in the fore section of the spring.
Problem with this development is the wide variability of inside dimensions on OEM pistons. But it is an idea that merits more thought and, perhaps some development.
The other areas that I have already researched into and created solutions are the weight of the piston, securing the spring to the piston, and reducing the piston's tendency to bounce by making the compression chamber walls "grip" the piston.
Last thing that I think is important to say is that the S-N curves of metal fatigue are linear on a logarithmic scale. That means that for every little problem we solve, we can gain one order of magnitude of life cycles. Conversely, every degree of freedom we allow to the spring's "flailing" reduces the life of the spring by an order of magnitude.
A spring that, if it was short, and contained, and had no bounceback, and . . . would last hundreds of millions of cycles, when given all the freedoms that exist in an airgun, reduces its life to mere thousands.
Anyway, thanks again for the discussion!
Hector
-
Hector-
thanks for your quick answer-so heavier pellets cause more bounce back than lighter pellets-because the pressure in the barrel is higher when the piston slams down- because the barrel volume under the pellets is less with the heavier pellet- so more pressure means more bounce back-
causing more "weird" backward compressions-and this breaks springs probably for the same reason valve float broke springs in the "old days" hence the pretty complicated but pretty cool Ducati solution-
heah-why couldn't air guns "catch" the piston(in a way like ducati) and PREVENT it from bouncing-control its motion-lock it forward?
No wonder one of those papers suggests spring guides to prolong spring life (guessing those guides scrape off-friction-some of the "bad rebound" energy-or at least keep is linear-not much wobble up and down)
A question
1)-does my RWS 460 have a guide??($360 new)-looking at diagram seems to show an inner guide-and hard to tell but maybe the piston is hollow-and acts as an outer guide??
Mike-I still find it hard to believe that 5000 cycle life-when motor valve springs get 1 BILLION- couldn't be "price" solved-
your 40 year old Kawasaki-10,000 RPM- maybe 80 per second(guessing those aren't the OEM springs-or tops-)-
But hector assures us air gun springs are equal in quality to pricy car springs-
and that makes sense since even pricy car springs-pricy brands and fast cars-are CHEAP
5000 cycles vs 1 BILLION- a violent 1 BILLION cycles-all because of a little bounce/float
Hey you guys much have watched that history channel Tacoma Narrows bridge failure-I don't know how much resonance you can get in 20/1000 second-all those back and forth compressions-(but less and less not like Tacoma bridge?)
but 5000 cycles-YIKES!
Never would have guessed 5000 cycles!
Charlie;
You are absolutely right. Someone should do something to "catch the piston", and I have done a few things when someone asks me to create a gun for heavy pellets, specially in the Diana sliding compression chamber full size family (48, 52, 54, 460, 56, & 470):
For one I use a heavier piston. The reason should be clear by now: if the mass of the pellet creates inertia that creates bounceback, an increase in the mass of the piston RESISTS better that bounceback.
Secondly, I use an Integral TopHat in my pistons. This "grips" the spring and makes the spring and the piston one unit. Again, this adds mass to the piston, but also avoids the condition where a longitudinal wave travelling in the spring can "separate" the spring's face from the piston (the spring bouncing back independent of the piston because the spring is lighter and can move faster).
Thirdly, the architecture of the ORing seal creates an expansion of the ORing if the piston tries to move back with any real speed, therefore "gripping" the walls of the compression chamber. In the mathematical model this would be like increasing the friction of the piston to the compression chamber ONLY at the end of the compression cycle.
With the new ideas that came out of this discussion, I think I will try a sleeve inside the piston to act as an outside guide to the spring. Of course that will limit me to use either Titan or Maccari springs, as a sleeve tight enough to really contain the spring would interfere with PG-2 kits, but both remaining springs are good quality anyway.
Yes your 460 has an OEM guide. Inside guide. It is somewhat loose to get the most power out of the platform, but do not worry, if / when your OEM spring breaks, you have several choices: You can use a Vortek made OEM-substituting spring. Those are designed to be a tighter fit to the OEM guides. You can replace the whole assembly with a Vortek K Yield kit, a Maccari ZRT kit, or have a custom guide made for the Maccari Monolith spring. You can also get a Titan # 14 spring and make a custom guide.
You have choices, from $19 to $200.
What were you saying about "how fa$t you want your bike to go?" ;)
Keep well and thanks!
Héctor
-
Unfortunate that the technology didn't work for you. It works well, and reliably for me, but not that I am a target match shooter.
I find the NP pistons easier to cock in my magnum rifles compared to my similarly rated conventional springs guns. Plus, the pressurized gas is not prone to the same harmonics as mechanical springs, not to mention the twisting and flexing inherent in the coil design.
And the cartridge design makes replacement so much easier for gas rams as compared to coil springs. No need for spring guides or damping tar.
Head to head comparison; I'll choose my Benjamin NP XL over my Hat Pat any day, and even my NP2 over the 350 purely for the ease of shooting cycle. Similar powers, but the rams are lighter, better balanced, and easier to shoot.
My 460 may still be my most accurate shooter out to 30 m, but this probably more due to its general workmanship than its spring. I would love to see a 460 equipped with a gas ram instead of the spring; I can't help but think it would be an even better shooter for reduced twang and noise, and with a smoother shot cycle.
JMHO Your results may vary.
.
As I said, Kim I still have hope in the technology. In a couple of months or so I should receive the parts from Germany to changeover a 48 to an N-Tec 48, I would love to use the solution in the 54, but to judge differences the 48 seems a better platform; we'll see then how things TRULY compare.
Depending on how that works, changing from a coil spring to an N-Tec powerplant should be a question of a change of piston and trigger, something that should cost around $200 at most. Is this worth it? I don't know, but the great advantage of the Diana line is that most new technologies are completely retro-fittable into older guns.
So, stay tuned!
;-)
Keep well and shoot straight
Hector Medina
-
Thanks, Mike!
The current Vortek PG-2 systems use an inner guide (very normal), and an outer guide (so far, only Vortek uses it). BUT they are both at the rear, as you know.
What I am envisioning is a system that would "encase" the spring. On the inside from the rear, and on the outside from the front. MOST systems nowadays use a TopHat (an inheritance of the die and stamping industry). But if the TopHat was extended backwards to surround the spring, we could have a system that is not piston mounted (you do not really want to alter the weight of the piston), but that works as BOTH the TopHat AND the outside guide.
In the common systems, the fore section of the spring is completely unsupported, both on the inside and on the outside and, while this will prevent the breakage of the rear section of the spring (most common), it will not prevent all the havoc in the fore section of the spring.
Problem with this development is the wide variability of inside dimensions on OEM pistons. But it is an idea that merits more thought and, perhaps some development.
The other areas that I have already researched into and created solutions are the weight of the piston, securing the spring to the piston, and reducing the piston's tendency to bounce by making the compression chamber walls "grip" the piston.
Last thing that I think is important to say is that the S-N curves of metal fatigue are linear on a logarithmic scale. That means that for every little problem we solve, we can gain one order of magnitude of life cycles. Conversely, every degree of freedom we allow to the spring's "flailing" reduces the life of the spring by an order of magnitude.
A spring that, if it was short, and contained, and had no bounceback, and . . . would last hundreds of millions of cycles, when given all the freedoms that exist in an airgun, reduces its life to mere thousands.
Anyway, thanks again for the discussion!
Hector
[/quote]
Hector
I wonder if a Vortek kit could possibly be modified to use the rear outer spring guide in front around the spring inside the piston as you are suggesting with a top hat made so that it would be a tight enough fit in the forward end of the Vortek guide and spring to do as you have suggested by locking the top hat and guide to the front of the spring. Since the Vortek outer guides fit the spring for the gun they are intended for quite well and are designed to go into the piston when cocked I believe for the most part it would only require some minor machining to the guide to make it fit on the other end of the spring and reside at the front of the spring not the rear and could have the hole for the top hat machined to a snug fit on the top hat so it would all be basically one piece.
Once assembled onto the front of the spring it would be mostly a single unit of spring, guide and top hat as a locked together unit.
I am also very interested in your experiment with the n-TEC ram in the D48 platform since I have one and with a Vortek kit in it and even though its a soft tune kit it is still a scope breaker and has killed two Hawke varmint scopes to date. The SF adjustments goes out of calibration to the point that at one time it will show the correct yardage for the actual distance shooting and then after that shot it will be blurry and when adjusted will read up to 50 yards different and back and forth from there with every shot. Hawke has been very good about replacing them but I would like to be able to shoot it with out playing musical scopes.
Mike
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Hector
I wonder if a Vortek kit could possibly be modified to use the rear outer spring guide in front around the spring inside the piston as you are suggesting with a top hat made so that it would be a tight enough fit in the forward end of the Vortek guide and spring to do as you have suggested by locking the top hat and guide to the front of the spring. Since the Vortek outer guides fit the spring for the gun they are intended for quite well and are designed to go into the piston when cocked I believe for the most part it would only require some minor machining to the guide to make it fit on the other end of the spring and reside at the front of the spring not the rear and could have the hole for the top hat machined to a snug fit on the top hat so it would all be basically one piece.
Once assembled onto the front of the spring it would be mostly a single unit of spring, guide and top hat as a locked together unit.
I am also very interested in your experiment with the n-TEC ram in the D48 platform since I have one and with a Vortek kit in it and even though its a soft tune kit it is still a scope breaker and has killed two Hawke varmint scopes to date. The SF adjustments goes out of calibration to the point that at one time it will show the correct yardage for the actual distance shooting and then after that shot it will be blurry and when adjusted will read up to 50 yards different and back and forth from there with every shot. Hawke has been very good about replacing them but I would like to be able to shoot it with out playing musical scopes.
Mike
Hiya Mike!
Vortek uses a number of washers inside the outside guide (he, that sounded funny!), one of them is steel (to allow the spring to turn), the other is an elastomer. These two washers contribute SIGNIFICANTLY to the smoothness of the Vortek kits.
Getting the spring to "grab" the piston when the rear Vortek guide lip has been machined off may be complicated, but you are right, let me look into it.
IF the piston can be grabbed by the spring (as in my current HMO pistons), then there really is no need for a top hat. The Top Hat's MAIN job is to center the spring on the piston stem and therefore impede the springs from developing a bent.
The OTHER role of the TopHat is to create a vaccuum between spring and piston if the spring wants to bounce back independently of the piston (as I usually do with the Walthers). This, while not "grabbing" the piston as in a mechanical fit, still reduces noticeably the bounceback, and therefore, will prevent breakages.
BTW, Titan (UK) springs are wound in such a way that the OUTSIDE of the spring is a close fit to the inside of the piston. I MAY try the Beehive egg-shaped ends (now that you explained to me what they are) and see if there is any advantage. Since the wire diameter is pretty much what we use here, the inside guides are HUGE, but those are stationary, so they do not contribute to the general entropy/havoc of the system.
I gave up on Hawke scopes a LONG time ago. I have not tested their AG SF models, those should be much better prepared for the 48 than their Varmint line. Perhaps youy should think about upgrading to one of them next time you have a chance ( http://www.hawkeoptics.com/airmax-30-sf-riflescopes.html (http://www.hawkeoptics.com/airmax-30-sf-riflescopes.html) ) .
USUALLY. MOST of the time, when a gun kills scopes (D54 excepted), it is the seals the ones you should inspect first. The D48 is a powerhouse, but it should not kill (especially with a soft tune) Air Gun rated scopes. Reason is simple: even with an artillery hold, the weight of the system resisting recoil is the gun+scope+torso+arms and hands, this is a much greater weight than in the 54, where only the action and the scope are resisting the recoil. The proportion is about 10 to 1.
IF the seals are not right or if the timing of the gun is not right, whether gas spring/strut/ram or metal spring will kill the scopes regardless of whether they are airgun rated or not.
JMHE
I'll keep you all informed.
Keep well and shoot straight!
Héctor
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Hector
That's kind of what I was thinking with the Vortek outer guide inside the piston but was not aware that it could work just as well without the top hat since I thought the top hat ( at least the steel ones ) where not only to center the spring but add some weight to the front of the piston to reduce bounce back that you have described here and allow the spring to live a longer and happier life. I was not aware the top hat being adhered by a small amount of grease to the front of the piston had that much of an effect on bounce back from the suction that the grease has on it.
I am interested in how the beehive springs work in a spring gun since as we have discussed here about the big difference in length versus diameter between engine springs and air gun springs. It will be an interesting experiment to see if the reduction in harmonics and fatigue gained in a engine is also transferred to the same design spring in an air gun. Inquiring minds want to know.
I do think I have some issue inside the 48 that is causing the piston to have hard contact with the compression chamber when fired like the seal is not standing proud enough of the piston to absorb the pistons impact with the end of the chamber without hard contact. It shoots JSB 10.34s at 870 fps so its not leaking compression at all. I have not had time to tear into it to verify my preliminary diagnosis as of yet. After the two scopes it broke were sent back to Hawke they called and offered me an upgrade to a Airmax SF 30mm tube for only pennies more so naturally I jumped on it but that scope went on my Mrod FT gun since it was just to nice to go back on the 48 and honestly I did not want to break it until I can confirm my suspicions of the piston making hard contact with the chamber.
I was told by the Hawke rep that called they would still continue to honor their lifetime warranties on all scopes regardless of what gun they were mounted on and would replace the varmint scope if I did not want to upgrade. He also recommended that if the scope was going on a spring gun regardless of low or high power that Hawke advises to use a 30mm scope instead of the 1 inch models. So before a scope goes back on the 48 it will be inspected as you say for damaged seals and repaired accordingly.
Mike
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Built many many engines for some extremely top names in racing, used many beehive springs, mostley for clearance, we could use higher lift cam profiles without coil bind. remember the lifter follows the cam and its not as violent as you would think, big difference in a ten inch spring and a 3 inch spring when it is compressed. David
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David
Agreed on the beehive springs and higher lifts achieved but a valve spring opening and closing at 10k rpms is quite violent albeit at a very short distance as compared to an air gun springs long compression range. Especially if its a hydraulic lifter since the cam profile is very steep on the initial opening ramp to set the lifter into the hydraulic lock situation it needs to open the valve with the least amount of loss of lift, solids are not near as aggressive on the opening ramps. Each has it own parameters it must live in to survive.
Mike
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Hector
That's kind of what I was thinking with the Vortek outer guide inside the piston but was not aware that it could work just as well without the top hat since I thought the top hat ( at least the steel ones ) where not only to center the spring but add some weight to the front of the piston to reduce bounce back that you have described here and allow the spring to live a longer and happier life. I was not aware the top hat being adhered by a small amount of grease to the front of the piston had that much of an effect on bounce back from the suction that the grease has on it.
I am interested in how the beehive springs work in a spring gun since as we have discussed here about the big difference in length versus diameter between engine springs and air gun springs. It will be an interesting experiment to see if the reduction in harmonics and fatigue gained in a engine is also transferred to the same design spring in an air gun. Inquiring minds want to know.
I do think I have some issue inside the 48 that is causing the piston to have hard contact with the compression chamber when fired like the seal is not standing proud enough of the piston to absorb the pistons impact with the end of the chamber without hard contact. It shoots JSB 10.34s at 870 fps so its not leaking compression at all. I have not had time to tear into it to verify my preliminary diagnosis as of yet. After the two scopes it broke were sent back to Hawke they called and offered me an upgrade to a Airmax SF 30mm tube for only pennies more so naturally I jumped on it but that scope went on my Mrod FT gun since it was just to nice to go back on the 48 and honestly I did not want to break it until I can confirm my suspicions of the piston making hard contact with the chamber.
I was told by the Hawke rep that called they would still continue to honor their lifetime warranties on all scopes regardless of what gun they were mounted on and would replace the varmint scope if I did not want to upgrade. He also recommended that if the scope was going on a spring gun regardless of low or high power that Hawke advises to use a 30mm scope instead of the 1 inch models. So before a scope goes back on the 48 it will be inspected as you say for damaged seals and repaired accordingly.
Mike
I am glad you are getting a good service from Hawke. I was not so lucky.
If your piston seal is good, check your breech seal by MAKING ABSOLUTELY SURE THE GUN IS UNLOADED AND UNCOCKED and blowing with all your strength into the barrel. IF air escapes, even slowly, then you need to replace that seal (make sure that air is not escaping between plastic muzzle piece and barrel).
Also the tightness of the closure. Cocking lever should stop about 1½" from closure and the rest should be closing pressure. Depending on the seal you are using closing force may be higher or lower, but the distance to closure is pretty much uniform.
IF you still think that it is a question of hard contact between piston and compression chamber end, then I would have to wonder if that contact is on the first compression cycle or on subsequent ends of bouncebacks (the first one being the most important, of course), and then the ONLY way to reduce that, if you have tried all other possibilities, is by using a lighter pellet.
Good luck with your 48! Indeed 870 fps for a 10.3 grainer is an excelent power level.
Keep well and shoot straight!
Hector
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If you don't want to put your mouth over the muzzle, you can use a length of rubber heater hose over the end of the barrel for the same effect. ;)
Cheers,
Smoketown
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Hector and Jim
I have the delrin breech seal or whatever material it is that ARH sells for the 48 in it but have not tried the pressurizing the breech seal that way to test for leaks, I have done the tissue paper test and see no movement from it when firing. No front sight just a muzzle weight/brake with factory shroud in place.
My cocking lever is preloaded about 1 1/2" from closed so I believe its closing tight. I hear what sounds like a metal to metal clank noise when shooting but cannot tell if its on the first compression cycle or second or possibly third.
So just need to test breech seal and if its good then take it apart and see if seal is proud of piston nose or not and see if any evidence of hard contact.
I have COPD so not sure if I can create enough pressure on the breech seal myself but have a large syringe I can rig up a fixture to use it to pressurize the breech seal and determine if it leaks down or not.
Mike