Question about heavy pellets for a .177

[Hanabata808]

I've read that using excessively heavy pellets can prematurely damage the spring in our guns. My question is does this apply to .177 users where the same gun is also available in .22 (which obviously has access to much heavier pellets)?  Since a standard lightweight .22 pellet is around 14gr, would that not mean that something like a .177 10.5gr CP heavy be fine for the same model gun in .177 configuration (assuming the powerplant/internals are the same)?
Taking a TX200 as an example... since they are available in .177 and .22, wouldn't it be safe to use a 10.5gr heavy pellet in the TX200 since that same powerplant will be subjected to a 14gr pellet in its .22 flavor?

Just a question that I was pondering. Not that I have any particular desire to use such a heavy .177 in my accurate springers. I was just genuinely curious about this subject.

[BenjiHunter]

There's a thread about this but I can't find it.
I know it has something to do with air volume and friction.

[Mark 611]

The AA guns such as the TX's and Pro Sports have a wire dia of 128/29 and will handle the 10.5gn pellets! if the wire size was any smaller I would get ready to change out the spring sooner! but spring are consumables like seals and will need to be replaced sooner or later anyway so why not just enjoy the rifle! JMO

[Doctorsolo]

I've read that using excessively heavy pellets can prematurely damage the spring in our guns. My question is does this apply to .177 users where the same gun is also available in .22 (which obviously has access to much heavier pellets)?  Since a standard lightweight .22 pellet is around 14gr, would that not mean that something like a .177 10.5gr CP heavy be fine for the same model gun in .177 configuration (assuming the powerplant/internals are the same)?
Taking a TX200 as an example... since they are available in .177 and .22, wouldn't it be safe to use a 10.5gr heavy pellet in the TX200 since that same powerplant will be subjected to a 14gr pellet in its .22 flavor?

Just a question that I was pondering. Not that I have any particular desire to use such a heavy .177 in my accurate springers. I was just genuinely curious about this subject.

I was thinking the exact same thing. I have no data to support this hypothesis, but it sounds reasonable to me. I'd like to hear what the resident spring and dynamics experts have to say.

[Mark 611]

if you guy's would do some research here in the search eng I think you'll find all the answers your looking for! this subject has been hashed out here many many times. not tryin to be funny just tryin to point you in the right direction!

[thekid]

With a chrono it is easy to determine what is good and what is not.
My 34 .177 was a 15fpe shooter with 7.9 gr crosmans, when I used the 10.5gr crosman heavies, it was only a 12.5 fpe shooter.
That tells me they are too heavy and stressing the machine, you should be looking for the optimal performance, and feel of the gun. Once you have an idea at what weight pellet gives this, then you search for the most accurate in that weight class.
My 34 .177 now has the JM OS kit, which utilizes the spring from the AA guns, it is now a 13 fpe shooter, with 7.9gr crosmans. The heavies drop the fpe to the 10.5-11fpe, so I stay away from those in this gun now.
Testing will help you come to the conclusion, giving you the answers you are looking for.

[Hanabata808]

if you guy's would do some research here in the search eng I think you'll find all the answers your looking for! this subject has been hashed out here many many times. not tryin to be funny just tryin to point you in the right direction!

I had a feeling this response might come up (even if it wasn't intended to be harsh) 
I actually did do a few searches, but searches like "heavy .177 pellets" and "heavy pellet spring damage" didn't come up with as much info as I thought, which is why I thought I'd be specific about this particular question.

I didn't come up empty-handed however. There were some interesting information which I'll paste into here:
(and maybe I should have pasted these initially anyway)

from Paul68:
A couple things to keep in mind are that although power plants can be indentical from one caliber to another, the larger caliber rifles tend to produce a little more FPE than the smaller calibers. While the power plants have the same power potential, the larger calibers seem to do better at transferring the energy to the pellet. I think this is because the larger surface area of the larger caliber pellet gives the pressurized air more surface to act on.

Also, in 177, when dealing with magnums its important to consider that you just can't push as heavy a pellet as you would in 22 cal even though the powerplant might be the same. For the same reason as a above, the smaller surface area of the 177 pellet seems to limit how effectively you can transfer energy to it. So although say a Hatsan 125 in 22 cal might be able to produce 29-30 fpe with a 21 grain pellet, the best you'll get out of a 125 in 177 is about 25 -26 fpe with a 10-11 grain pellet (Tried it)   In the mid power guns, you'll generally see similar fpe across 177 and 22 cal, with 22 cal maybe showing 1-2 fpe higher. The magnums though produce so much power, the disparity grows bigtime.

and

from CDT:
Ian Pellant, a well known and respected expert in the field of airguns came to the conclusion that a springer that is designed to shoot both .177 and .22 pellets that you should be able to shoot as heavy .177 pellet as you like.

I agree but disagree with that theory. Most pellet guns today are designed around a power plant and spring using a wire diameter of /119 to .123 for a .177 and capable of shooting .22 pellets whereas the heavier magnum guns of today are based on .22 or larger caliber using a .128 dia, or large wire. A spring of that size would be able to handle any weight pellet.

Of course there's a lot of "just shoot what your gun likes!" answers in those threads too. But that doesn't help break down the nitty-gritty details of my particular question.
But thanks for the replies so far guys. I'll keep digging. I think it's a pretty interesting topic.

[Mark 611]

OK your right I sure don't mean to sound harsh in any way at all! but I will say from my experience if your using a 128 wire or bigger you can shoot the 10.5's and the wire will handle this weight! as you have found in the info you have dug up their are other respected folks here who also agree, but also like Rob has said you really need to test your rifle to see how it performs! also factory springs don't compare to JM, V-Mach or Vortek's wire technology JMO

[Paul68]

The idea behind pellet weight is to find a pellet that allows your gun to make the best use of the energy it produces.

The transfer port on an airgun can only allow so much air to pass at a certain rate, thus basically making the amount of potential FPE the rifle can produce a constant based on its working volume. There are extremes, such as if you made a huge cylinder with extremely powerful spring, but then you would completely surpass the transfer ports flow rate, but that's irrelevant here. Wer'e assuming the basic transfer port size used by most manufacturers.

 When the force required to push a pellet surpasses a certain point, the pressure in the cylinder can become so high that the force exerted by the spring and piston is no longer able to overcome it. Also, keep in mind that with a coil spring, force drops as the spring becomes uncompressed. The result is piston bounce and potential spring damage or failure.

The idea is to find a pellet that allows the pressure to reach an ideal level before pushing the pellet down the bore. Too high and the piston bounces, too low and it slams into the bottom of the cylinder, just right and it pushes the pellet down the bore with a following gradual lowering of pressure that allows the piston to come to a soft stop.

Pellet weight is only part of the equation. The size of the pellet also plays a large role in how high pressure buildup within the cylinder will be. The smaller surface area of the 177 pellet will lower the amount of force that is applied, thus increasing pressure. A larger 22 caliber pellet allows more force to be applied, thus reducing pressure. Basically, pressure increases as area decreases, and vice versa.

The larger surface area allows more force to be applied to the larger pellet, resulting in lower pressures despite a heavier pellet, which means more energy transferred to the larger mass of the larger pellet. So, since pressure will not spike as quickly with the larger pellet, you can also have greater weight since more energy can be utilized. The result is a pellet that is launched with more energy.


The smaller pellet increases pressure without allowing as much energy to be transferred to the pellet. So, since the smaller pellet is already increasing pressure, and more force is required to move a heavier mass, if you also increase the weight of the smaller pellet, you then increase pressure even more, to the point of causing an excessive spike in pressure.

That's pretty much why you are limited in pellet weight with a 177 despite the powerplant being the same among 22 cal versions also.






 

[robert w]

if you have a 177 gun that is way too fast like over 1000 fps shooting 7.5 weight pellets it wont be accurate and heavy pellets will tame it down without any damage to the spring. its just reverse of shootin pba in any spring gun its not good at all. so if your gun shoots fast and wont shoot groups ,try heavy pellets . if your gun is under 900 fps it dont need heavy pellets unless you think you need them . magnum power does best shooting heavy . thats my p.o.v.

[Hanabata808]

Thanks Paul68. That was a pretty clear explanation that even I can understand.  That whole issue with given the same powerplant, it confused me as to why the .177 would be harder on the spring than a .22 of the same given pellet weight. I didn't realize the transfer port would play such a large role. Very interesting stuff to me! Thanks!

Oh and  Mark611 I didn't mean to imply you were being harsh at all.
Master Yoda can do no wrong 

[Paul68]

I only understand it on a basic level, the big brains around here could break it down better in more detail with numbers and circles and arrows;)

[rivraton]

I realize this thread is old, but I am new here and as I was reading it I recalled a discussion about "Dieseling" & "Detonation". From what I gathered the sprig damage caused by using heavy pellets is due to "Detonation".  The difference between having one or the other, I think, boils down to "compression ratio"; lighter pellets move earlier and the "combustion chamber" increases in size there by lowering the compression ratio so detonation is less likely. Heavy pellets initially move slower and the ratio remains higher so detonation is more likely. With the larger .22 bore the ratio starts out lower so it's a non issue. If I am correct you should be able to seat the heavy pellet deeper (lowering the ratio) to counter the effect.
Comments?

[donw]

OK your right I sure don't mean to sound harsh in any way at all! but I will say from my experience if your using a 128 wire or bigger you can shoot the 10.5's and the wire will handle this weight! as you have found in the info you have dug up their are other respected folks here who also agree, but also like Rob has said you really need to test your rifle to see how it performs! also factory springs don't compare to JM, V-Mach or Vortek's wire technology JMO

[/b][/i][/u]

a key factor IMO

[nced]

I realize this thread is old, but I am new here and as I was reading it I recalled a discussion about "Dieseling" & "Detonation". From what I gathered the sprig damage caused by using heavy pellets is due to "Detonation".  The difference between having one or the other, I think, boils down to "compression ratio"; lighter pellets move earlier and the "combustion chamber" increases in size there by lowering the compression ratio so detonation is less likely. Heavy pellets initially move slower and the ratio remains higher so detonation is more likely. With the larger .22 bore the ratio starts out lower so it's a non issue. If I am correct you should be able to seat the heavy pellet deeper (lowering the ratio) to counter the effect.
Comments?

I have some personal experience with .177 CP heavies vs CP lights because my brother used to shoot 10.5 grain CPHs exclusively using a .128 wire aftermarket spring and shooting a couple cases of CPs per year. I could count on replacing his aftermarket spring about every two years due to breakage. Then years ago my brother learned that the flatter trajectory of the 7.9 grain CPL trumped the less wind drift and greater penetration of the CPH for his squirrel hunting. Since switching to the 7.9 grain pellet I've only replaced one spring .128 wire since, and the spring that did break shot 10.5 grainers for much of it's "life" before switching to the 7.9s.

While DETONATION does wreak havoc on a spring (springers all diesel a bit when lubed with hydrocarbon based lubes), I have a personal THEORY (just that, only a theory) that the heavy pellet requires more force to "pop the leade"  so the piston rebounds on the air cushion before the pressure is released. The piston is rebounding at the same time the coils are still expanding which creates a very high stress on the coils at the point of the "convergence" of piston and coils bouncing back and the rear coils still surging forward. Just a theory here but I do know that heavy .177 pellets will shorten the "life" of a .128 wire spring in a R9.

As a side note.........I recently had a good .120 wire aftermarket spring break after years of service (10s of thousands of shots) so I took a pic of the break playing with my new (back then) relatively cheap Nikon CoolPix camera and annotated the pic using the free Gimp Image Editor...................
 
Seems that there was a minor surface flaw in the wire and the flaw "migrated" with use over the years. 

[Onebaddj]

In my 350 mags i run heavy 10.3 gr jsbs in the 177 and it handles them well but my big cat in 177 that is also available in 22 i use 8.4 gr. It just cannot get the 10.3 gr pellets moving efficiently.

[pappa]

This subject was totally hashed out the middle of this month. Following is my comment on that thread:

AirGun Gate / Re: Do heavier pellets really cause springs to fail prematurely in springers?
« on: May 15, 2013, 09:35:24 PM »
Not only do overly heavy pellets damage the rifle, they contribute to poor performance. As you get to a certain point in pellet weight, velocity and accuracy begins to fall off because you have overcome the ability of the design of a particular rifle to efficiently and accurately send the projectile to the aim point with enough power to do what it is supposed to do. In other words, you have exceeded the weight point of efficiency and instead of getting more power out of the heavier pellet, you are getting less because of a loss in velocity.

[pappa]

I always try to stick to a pellet weight that is just a little over the weight it takes to keep a rifle from going supersonic but still gives me good accuracy and killing power. I don't need any more than that and I keep an entire suburban neighborhood in NC free of squirrels!

[nced]

This subject was totally hashed out the middle of this month. Following is my comment on that thread:

AirGun Gate / Re: Do heavier pellets really cause springs to fail prematurely in springers?
« on: May 15, 2013, 09:35:24 PM »
Not only do overly heavy pellets damage the rifle, they contribute to poor performance. As you get to a certain point in pellet weight, velocity and accuracy begins to fall off because you have overcome the ability of the design of a particular rifle to efficiently and accurately send the projectile to the aim point with enough power to do what it is supposed to do. In other words, you have exceeded the weight point of efficiency and instead of getting more power out of the heavier pellet, you are getting less because of a loss in velocity.

Accuracy? I found that the 10.5 grain CP heavy "spring busters" can be the MOST accurate in some springers! Here are a couple 3 shot groups "back to back" when my brother was shootin' CPHs from his .177 R9...........

[Kowboi]

I shoot CP Ultra Mag Domed 10.5g pellets in most of my guns especially my Airhawks. They shoot the most accurate and I figure springs and seals are relatively cheap and easy to replace if need be. Guess I'm another "shoot what your gun likes" guy.