Springer Modification Thoughts

I wouldn't do it and it doesn't sound like a feasible idea. One thing I notice is a more harsh firing behavior when shooting light pellets.

Customairseals.com sells piston seals that basically do what you are thinking about. They soften recoil a bit better than standard donut seals and give a noticable power boost.

if you do try a dampener, i'd use rubber or even leather and superglue it in placei might cut the hole for transfer port a little larger , too - in case it does shift. i have used leather at the end of the spring where it seats around the spring guide - on a rws model 94. the spring guide is part of the trigger packet on those cometa 400 variations. felt would compress so much in there it might not give the desired effect. i have some black felt i bought from walmart sewing area. i use it to line the stock where the action meets the stock - usually cheaper plastic hollow stocks benefit from that. i have also used the black felt to dampen the noise from the cocking slot, but the cocking lever has to be hinged one - like a diana 350. most of the noise comes from the cocking slot, anyway. those hinged cocking arms allow for the wood cut out for cocking under the stock to be smaller and lets less noise out . hw35 is s good example of that. i use those round felt pads to put inside the pump arm where it meets the gun on the sheridans and benjis i fix. sometimes i just space up the rubber cushioner on the sheridans because they cushion the slap of your pump arm better than any other pumper company ive seen (i pray they bring back sheridan). but when i buy those felt ones, i see that they have a black spongy rubber pad kit beside it. i get them from the 99 cent only store. they have o-ring kits for a dollar there too. sometimes i need a slightly bigger oring for things like that 392 / 397 valve to seat in the tube tighter. now crosman has two orings there on top end of these newer valves which better prevents the air being pumped into the valve to escape around the valve body. i have began to use the hard rubber noise dampener for marauders in the disco/prod/2260 diameter tubes. i have to cut some away, but it worked so well , i thought i'd try it one the next one with that insulation that goes on your outside air conditioner line or copper tubing. i use that for the 2400kt stocks because that plastic slips off my should too easily and also to increase length of pull. well, the lighter spongier insulator padding didnt work as well as hard rubber - it ended up inside the prod valve i used and created an instant regulator......mustve taken 100+ shots to bleed that air out so i could see why it was shooting a consistent 450 fps. i learn from things like this, so i strongly encourage you. unless you hear not to from someone3 like steve pope - and if he didnt know , he'd tell you. email him at v-mach - i do. those damn hw underlevers are so expensive, there should be NO problems with that thing. maybe try it on a cheap gun first ? .......idk...... good thinking, tho. the only way you can make it big in the airgun industry as a newbie is to come up with something new that works without faultering. ....try it !! - paul.

Don't forget about the heat generated by compression- 500 plus degrees.Felt might not work.A thinned piston seal turned around or leather.We know leather will work from it being THE original piston seal.

 Thoughts,tune it down with a JM kit or Vortex....Is the gun consistent,are you consistent...I tell you this Fact,for me,what I have to eat can change my consistency....I shoot better when I eat bland foods and have a relaxed mind.

...I tell you this Fact,for me,what I have to eat can change my consistency....I shoot better when I eat bland foods and have a relaxed mind.

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Same here boscoe! If I'm constipated it's hard to relax and concentrate on the mil-dots when your sphincter nerves are sounding a five alarm warning, but the fire trucks can't get out of the station.... 



Kindly 'Ol Uncle 

What about some type of gel donut that could compress as the spring engages it and slow the spring to a stop. Shouldn't lose too much power if it takes place at the very last 1/4" or so.

Or, could the spring be attached to the opposite end of the chamber and the length modified so at it's full expansion, it stops just before slamming into the port end?

You will still have the reverse recoil, no getting around that.

However, could it be managed with a device that grabs the spring at it's full expansion and holds it from returning until the rifle is cocked again? There will still be some recoil as the spring shifts about, but not the harshness of a full recoiling spring.

I'll hang up and let the more knowledgeable members voice their ideas/opinions. 

A well tuned spring gun already has a piston damper built into them. It's an air cushion. Well set up and tuned the piston stops not so much from the front of the compression chamber coming into contact with the piston seal. But from the compressed air that is pushing on the base of the pellet. A poorly tuned gun will be so over spring that the pellet has left the barrel allowing the piston to slam into the front of the air chamber.

Many variables can affect this, that is why good spring gun tuners are so sought after.

just my 2 pesos worth

Hairsmith

Don't shoot really light pellets. My springers never have liked them. Harsh and inaccurate.

A well tuned spring gun already has a piston damper built into them. It's an air cushion. Well set up and tuned the piston stops not so much from the front of the compression chamber coming into contact with the piston seal. But from the compressed air that is pushing on the base of the pellet. A poorly tuned gun will be so over spring that the pellet has left the barrel allowing the piston to slam into the front of the air chamber.

Many variables can affect this, that is why good spring gun tuners are so sought after.

just my 2 pesos worth

Hairsmith

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" A well tuned spring gun already has a piston damper built into them. It's an air cushion."



Exactly, that was my point about not using light pellets in springers.

+1 for Hairsmith. A properly designed springer, such as those produced by HW, does not allow the piston to slam the end of the chamber wall. This air cushion is the cause of piston bounce. As stated above there are many variables involved to design or tune a springer. There is a delicate balance between maintaining an air cushion and minimizing piston bounce.

Perhaps EKM could help explain.

" A well tuned spring gun already has a piston damper built into them. It's an air cushion." green ball for that comment. i have found that it is very serious business to widen or choke this transfer port area, as the perfect amount of back pressure can be an excellent springer to shoot. just a tad too big and the gun actually looses power and is harsh shot cycle. many of the truk webleys i sold were intended for the australian market and were less powerful. widening the transfer port, or drilling it out to make it slightly bigger produced fac power (from 860 fps to 980 with 8 grainers) but i ruined a few as i learned about the transfer ports of springers. maybe even more important than harmonics or the balancing of the barrel during recoil . another thing to consider is what made the sterling hr 81 and 83 rifles a bad design - the way that the piston seal slams into the end of the air chamber needs to be with out areas or channels that will deform the piston seal. the webley paradigm had really cool air channels cut into the inside of the air chamber which helped funnel air into the transfer port - it a pnuematic , and i wanted to do this with spring piston guns, but it would have deformed the piston seal. - paul.

I recently purchased an HW97. From the factory it was doing 15ftlbs. It was harsh and a bit buzzy. I installed a Vortek kit and the power was right at 15 ftlbs, but no buzz. A very quick thunk sound, but it was still more hold sensitive and lively than I wanted. I then installed a 12 ftlb spring. That made a world of difference. It's not hold sensitive at all. I can shoot it as well as any of my PCPs. I can shoot 1/4" to 3/8" groups at 25 yards all day. I highly reccomend the Vortek 12 ftlb kit.

Good luck!

Mike

 



From the Cardew book on spring guns: "A graph of typical piston travel against time is shown in fig 5.1, it can be seen that the velocity is approximately constant after the initial acceleration until it nears the end of the cylinder when it slows down abruptly and stops for an instant at about 1/10 inch from the cylinder end. From this position it bounces back to a point nearly 1/2 inch from the cylinder end, it then returns and comes to rest against the end of the cylinder. The reason that the piston is forced back, or bounces, is because at the instant that the piston is at the front of its stroke, the air is at it's highest pressure; now the air is not able to transfer it's energy instantaneously to the pellet since the pellet requires time to accelerate. Hence the highly compressed air forces the piston backwards until the forward thrust of the spring equals the backward thrust of the air."

With the gun they were testing, they determined the max pressure to be 1366psi and temperature of 1500°F This is adiabatic compression where there is no transfer of this instantaneously heated air to its surroundings.

IMO...because of physical design and materials, springers ARE limited in output.

what one must do is to match the rifle with the pellet and game/target use it's intended for.

i've found my preference is toward higher dollar springers such as the AA ProSport and RWS 54 and the HW 90 series rifles. they tend to be of better quality from the factory and matching the correct pellet(s) becomes easier.

the HW 90 series/Theoben system is very tunable by simply adjusting air pressure but they can be harsh in their recoil, too.

the biggest "enemy" of the springer is the metal-to-metal contact generated by spring to receiver contact. proper lube is probably the best way to minimize noise made by a springer.

My hearing is not so great, so when I shoot this Weihrauch HW97K outside, all I hear is the action. I don't hear any report from the muzzle at all. I do if I shoot it inside, but not outside. So are you saying that the action sound that I'm hearing isn't the piston slamming against the end of the compression chamber? I thought that's what causes the forward recoil. ???

And thanks, guys, for all of your input. It's much appreciated.

And yes, how I feel -- physically, mentally, or spiritually -- when I'm shooting makes a BIG difference, too.

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The sudden deceleration of the piston is what causes the forward recoil - even with the air cushion described, the piston still goes from moving forward very quickly to stopped (in fact, actually bouncing backward a tiny bit) in just milliseconds. All the violent mechanical commotion is responsible for most of the sound a springer makes, but not all of it, which is why even on something as tame as an HW30, an LDC will quiet things down some (which is why AOA sells the "Urban Pro"). The difference becomes more noticeable as you go up in power. I recently tried an LDC on my 19 fpe R1 and can confidently state there is definitely a difference, but still plenty of mechanical commotion as well.

But anyone who has ever dry-fired a springer accidentally can attest to the fact that it is a LOT louder when you do - no mistaking that sound for a normal shot because of the lack of air resistance cushioning the piston.