detuning magnum springers to medium power ???

[Petey]

Keep in mind, the big magnums also have heavier piston assemblies, so even though you lower the spring power and get the gun putting out FPE similar to its little brothers and sisters, it will still have more recoil even with the slightly heavier body. Springers are a balancing act, and everything is built to work as a part of the whole. The better route is to put that effort into smoothing and tuning. I've had many big springers, and I treat em just like their smaller siblings; if they cant do a dime or better at 25 yards, they need work. I've had the magnums doing under an inch at 50 yards, so to me, reducing the power in one is really counterproductive and taking away from the potential the gun was designed to provide in the first place. Just get a gun already at the power level you want, and choose a model with  a rep for accuracy. The 48's and 52's for instance are perfect candidates. Powerful, low hold sensitivity, and very very accurate.

does that rws 350 shoot 1/2 inch at 50 yds? that is PCP accuracy. plus detuning a magnum rifle you end up with a heavy 12 fpe rifle when there are many very accurate springers stock that are lighter and  at 12-15 fpe. it is like turning 4 wheel drive truck into 2 wheel drive

It's all pizza..what one likes another wouldn't touch and so on.... to each his own.   
I can tell you this.....that having had four shoulder surgeries , a de-tuned 48 is an all day shooter vs 30 min and put it away.
Had it out last week and shot it for three hours...Dime size groups at 25 yards....in fact , I can shoot staples off the target......so de-tuning has benefits you may not have considered.
As for de-tunig an RWS 350--- I would run away from that one ....get a 34. you can put an OS kit in it later.

Happy Shootin to All !
Petey

[angrytimes]

Don't avoid an under/side lever because of some pics you have seen. If you look after your gun and treat it with respect it is not goin to cut your fingers off. I reckon get a Diana 48/52. Accurate, lethal, quiet, back yard friendly (with a solid pellet stop) and best of all you will not even need to molest it and cut up it's spring because all of this gun possesses all of these great qualities from the factory! Match it with a heavy duty hawke sport hd and a bkl one piece mount and you will have a very solid and affordable package. The t-06 trigger is awesome and it's German made.

[Petey]

A 48 is not backyard friendly unless your yard is huge.... That short stroke ,large diameter bore pushes a lot of air....not exactly quiet. Again---de- tuned = far more quiet and with the right accessories it's even more quiet.
Either way a 48 is a great way to go.

 *** These Shrouds are no longer available= can't help ya ***

[angrytimes]

What's not back yard friendly about it? My mate shoots his 52 near everyday and his neighbours have never had a problem with it. It's a.22 so not super sonic so yeah it's quiet. If you don't have shoulder problems why would you detune it? They are hunting guns and you decrease their ability to kill. Just why? If you want a 12fpe just buy a 12fpe.

[D14Jeff]

conservation of momentum. decrease the velocity or increase the mass and it will kick less.

that's why
and i like to tinker

i got so wrapped in the beautiful stock on the 135 that i forgot i wanted something with a built in suppressor ...... sometimes i'm a dumb butt , LOL
are the hatsan 85 and 125 snipers very front heavy like the crosman/benjamins with their metal shroud ?
they aren't wood , but ATM detuning a metal spring 125 sniper ......
http://www.airgunproshop.com/hatsan-airguns/viewcategory.php?groupid=9
.... or a full power vorteked 85 sniper is looking more interesting .
http://www.airgunproshop.com/hatsan-airguns/viewcategory.php?groupid=20

the 85 more so cause i can get a refurbed 95 later and swap the stocks and resell the 95 in the sniper stock for about the same cost as the 95 . FWIU the 135 stock wont work on the 125's . but the vortek piston/ram gets a lot of good comments .
 my AP is in full force !! LMBO .

[D14Jeff]

HMMMMMMMMMMMM ......................

is a 125 or 85 sniper barrel a perfect fit on a 135 ?
if they will .... are they available anywhere in America ?

[Dick Tracey]

The 135 has a larger dia piston, therefore, I don't it is a direct swap.
That should make the receiver a larger dia.


DT

[D14Jeff]

well then i guess i'll get the 85 sniper when i'm ready and later on get a 95 and do the stock swap and sell .

[Benwaller]

conservation of momentum. decrease the velocity or increase the mass and it will kick less.

Airguns are all about physics.  Good answer.

As I recall Momentum = Velocity X Mass; and Energy = Velocity squared X 1/2 Mass but I've been known to be wrong. 

In any case increasing Mass can bang a spring pretty hard, but they are pretty cheap to replace.  And this "double hammer" which can develop under a heavy pellet, does not contribute to accuracy - been there, done that. 

Being somewhat a shade tree mechanic and since cheap springers are reliably cheap platforms upon which to test ideas, I have considered changing the porting in a modified 'Hawk I have, enlarging it slightly, so to relieve some of that double hammer that develops with a heavy pellet.  I figure if there is more air getting to the pellet sooner the dwell time will be reduced, the pellet will start moving earlier and more momentum will be going to the pellet and not back into the piston.  I don't actually know any of this for sure but it sure seems reasonable enough.

Seems to me that the trick will be to not over enlarge the port which would likely establish a rough shot cycle and ruin the gun entirely.

One of these days I'm gonna' do it.  There will always be another gun.

  Ben

[D14Jeff]

be careful enlarging the port . this guy seems to know what he's doing and needed to make a port smaller because ..... " There's a very slight metal "ping" at the end of the shot cycle which I attribute to the front of the piston kissing the face of the compression tube.

This is becoming a semi-trend lately and if you're a regular reader (thank you), you can probably already guess as to the cause(s).  The transfer port on the gun is pretty large.  The bore is also on the loose side.  I can fix the transfer port, so that's up next. ...... "

at the bottom of that article .... http://anotherairgunblog.blogspot.com/2014/03/webley-hatsan-patriot-piston-buttoning.html

heres the article where he made it smaller .... http://anotherairgunblog.blogspot.com/search/label/webley

[Benwaller]

I think this guy knows a lot about the subject no doubt about it, but his issue is a piston that is hurtling so fast and hard into the end of the compression cylinder that a metal-to-metal sound is being generated.  The characteristic that I am addressing is a bounce that occurs before the end of the stroke, which I think is being generated by the piston being flung back (however short lived that event is) by the slug of highly compressed air in the cylinder that is only there at that magnitude because the pellet is too heavy or the port is too small. 

Hmmmm.  Maybe all that has to happen is to clean up, fair in, the edges of that port.  I'll definitely do that first.

But if fairing the port proves insufficient I will bore out the port a little bit at a time, and re-fair, until that bounce is gone...or the cylinder port is so whacked that I'll have to order a new cylinder altogether and put the gun back together the way it is now, which is a really well-tuned rifle happy with 8 grain pellets.  Which is not the goal.  What I want here is a well-tuned rifle happy with Heavies.  I am not reluctant to test my ideas in pursuit of this goal.

Besides, failure does reliably encourage better work.  And I'm all about making progress.

  Ben

[mafatone]

I don't understand why people buy a magnum springer (like a HT-135, etc.) and then want to detune it. What was the point of buying it? You would have been better off buying a RWS 54 or similar which is known for their high quality and accuracy. Tar, clear tar, Moly, clear Moly, cutting coils from springs. Why would you even consider buying a magnum springer if you're going to this to it? I don't understand.......

[ptpalpha]

Well, cutting coils is a seperate issue, but tar and moly have been the standard for lube-tuning for decades.  I highly doubt there's one springer on the line at any high-profile FT or benchrest competitions that don't have Maccari tar on the spring and Maccari moly for the lube.
As for why you would want to cut a coil off the spring, there are many reasons.  First, you fell in love with that particular rifle and hate the harsh shot cycle.  Or, you like everything about a rifle but want to find out of knocking 50fps or so off her will improve accuracy.  Maybe, like a lot of us, you just can't help yourself when it comes to tinkering and experimenting with airguns.
Finally, like the OP states in his opening post, the idea would be to chop the spring to make the rifle more docile, learn the ins and outs of how to shoot a springer, then replace the chopped spring later once you get your skill level higher.
Let's face it, springers can be difficult to shoot accurately and consistantly, and magnum springers add many difficult to navigate variables to that equation. 

[D14Jeff]

Pappywith4 put a o=ring in his 125 and it looks promising . a %10 - %15 Fps reduction , less recoil and a noticeable increase in accuracy

http://www.gatewaytoairguns.org/GTA/index.php?topic=69933.msg676144;topicseen#msg676144

http://www.gatewaytoairguns.org/GTA/index.php?topic=69933.msg676234;topicseen#msg676234

http://www.gatewaytoairguns.org/GTA/index.php?topic=72651.msg692239;topicseen#msg692239

http://www.gatewaytoairguns.org/GTA/index.php?topic=72379.msg693678;topicseen#msg693678

i'm looking forward to his next teardown to see how it does over time .

[Paul68]

I think it comes down to basics, making the proper decision when buying a springer.

We always see a lot of threads where newbies want advice on buying a springer, but less commonly do we see either someone suggest the poster first decide what their needs and experience level are, or suggest a rifle that fits their needs/experience. This is the biggest mistake made when buying an airgun, and the biggest reason for so much discouragement and poor opinion forming of particular brands/models, or even airguns in general.

If some new shooter decides they want a handgun for home defense, you will never see experienced shooters suggest they get a 44 mag  shooting weak target rounds to make it more manageable. Same premise here.

For most folks, an introductory rifle should be light, docile, reliable, and reasonably accurate even in inexperienced hands. It is the time put in behind the trigger of such a rifle that prepares them for the later step up to something more aggressive. The basics of shooting form and procedure are best learned with a rifle that is forgiving, and trying to improve with something outside the realm of the intended purpose simply introduces an unneeded handicap.

Can you reduce the violence of a big magnum through modification? Sure. However, it will never be anywhere near as easy and forgiving a shooter as one of it half sized siblings. A Hatsan 125 for instance has a piston and spring over twice the size and weight of a D34 and a much longer stroke. You will never reduce the recoil in the 125 enough to make it as easy to manage as the 34. Even with the heavier overall mass of the gun.

 For an example, look at the RWS48 Sidelever, and the RWS350 Mag. I doubt anyone would argue that the 350 is easier to shoot than the 48, and in fact the opposite is true. The 48 is WAYYYYY easier to shoot and has a well earned reputation for accuracy and low hold sensitivity. However, both guns have a nearly identical weight and similar power ratio though the 350 edges ahead with 2-3 more fpe. Why is this? Because the piston assembly in each rifle is much different. The 350 uses a heavy piston with a long stroke to produce its power, which is why it is so hold sensitive. A lot of moving mass, with a relatively long lock time, means more movement lasting a longer amount of time. The longer that rifle is moving in your hands, the harder it is to maintain your aim point consistently, and add in the heavier moving mass of the piston, and you end up with a beast of a rifle. The 48 on the other hand has a slightly shorter stroke and lighter piston. Less moving mass and faster lock times simply means less movement, and quicker pellet launch. 

And if you do somehow manage to slow the piston down enough to get recoil levels even close to similar, we have to remember that air rifles are a balancing act in physics. You have then introduced a slew of other issues, including greatly increased lock times and greatly reduced power which directly affects trajectory. Basically, you have turned the gun into a slow and lumbering catapult that can actually be more hold sensitive because of the longer time it takes for the piston to complete its stroke and get that pellet moving.

Personally, I don't see much point in reducing power in a big magnum enough to detune it to the level of a "medium" power springer. I feel it would be wiser to concentrate on making the magnum as smooth and efficient as possible with a good tune and using it as it was intended, as a cannon of a springer meant to produce max fpe. For accuracy and ease of shooting, I would simply save myself the headache and get something intended for that purpose. 
 

[D14Jeff]

thanks paul68 . any idea how the hatsan 95/85 piston weight and stroke length compare to the 125 ? or how the 95/85 piston weight and stroke compares to the rws 350/xs28m or rws 48 ?

[Paul68]

Don't have all the direct specs for your comparisons. Here's what I do have.

The Hatsan 125 has a 120mm stroke with an 8" long piston and 29mm receiver.

The RWS350 has a 6.31" long piston and 115mm stroke and 28mm reciever.

The RWS34 has a 5.19" long piston and 80mm stroke with 28mm reciever.

The RWS48 has a 100mm stroke with 28mm reciever.

The Hatsan 95 has a 27mm receiver with 100mm stroke.

You can safely assume the longer pistons will be heavier even though we don't have the wall thickness.

[Airjason]

I had JM send me a low power spring for my R1 in .177. I wanted to lower the power on the R1 so I could shoot it indoors with less cocking effort and less noise. After changing the spring, the R1 chrono'd at about 740 ft/sec and I was happy at that. No twang. That was two years ago. Funny thing is that the gun now chronos at 910ft/sec. Somehow the R1 just broke in itself to the higher velocity. Oh well, I'll just leave it at that.

[BobbyHumphrey]

     I'm curious of weight comparisons also. I'd wager there isnt a piston much heavier out ther than a hatsan  125. Piston weight , swept volume , transfer port size and possible spring tension all charted. That would be interesting.

[Dick Tracey]

The Hatsan 135 will top the 125,  not sure about the weight.  There used to be a chart on the Web/Forums that showed a lot of these statistics, but it don't remember where it was.

DT