has anyone changed the air chamber size ???

[howie1a]

Has any one changed the air chamber the length of the air chamber by shorting the leather seal if you have a leather seal or putting a shorter seal in or cutting the piston back/ would this give more power to the pellet since now you have more air pushing your pellet down the barrel , What do you think ??? howie

[Splash]

I had thought of doing that a while back, but decided against it. The more I thought about it, there didn't seem to be enough room to make much of a diff. If you go back too far, then the seal would get chewed up by the cocking slot. Also with a bigger air chamber, there would be more pressure against the spring, so it may lose some fps. My thinking is way off base at times, so I could be wrong.

Mike

[howie1a]

The seal is in front of the cocking slot it dosn't go back far enough to tare it up with the seal sitting on the end of the piston it wouldn't get tore up. but the presssure is the big question you might have to up grade the spring or put some spacers in it to get more push. Just a thought maybe some of the guys think different but it is a neat thing to kick around. howie

Maybe I'm looking at it wrong, but if you shortened the seal (or piston or whatever) to increase the volume of the air chamber when cocked, wouldn't that also increase the air chamber volume when it was in the fully fired position? If that's the case, you wouldn't gain anything in the way of power or speed because the swept volume of the chamber hasn't changed.

While not totally analogous, in my mind that's sorta like putting dished pistons into an engine that had flat top pistons, which would reduce the compression ratio. Lower horsepower etc., all other things being equal.

Does that make sense? (it's always a crapshoot when I start trying to analyze this stuff in my mind ;~)

***Edit*** I just realized I'm probably looking at it wrong. I was assuming the front of the piston/seal would stop at the same place, and that's not likely the case, unless I'm looking at it wrong again ;~)***

Bryan

[howie1a]

In a car engine the piston is connected to a crank shaft that and the length of the connection rod controls  the stroke but a air gun has not stop orther than the fron of the chamber but when the spring gets the piston going even if the piston reaches it's full length you would still have forward motion ( objects that are in motion stay in motion ) also if their you need to use a spring compressor the spring can't reach it's full length so it would still have push.The piston stops it's forward motion when it reaches the end of the chamber it's got to hit maybe the air slows and acts like a cushion of air to help slow down the piston , and the extra air going down the barrel should keep pushing the pellet and maybe give the gun more power. I don't really know just trying to see in my mind what is happening. Howie

[fnash]

The forward stroke compression gives the power. The higher the pressure the higher the power, just as in an engine. If you shorten the spring, which would be like making the piston shorter would give less power as we all know, and lower FPS.  I just proved the point to myself about two weeks ago. I put a shorter spring in a B3 just to see the effect. As expected the FPS dropped about 50 FPS... It shoots smoother with less recoil but slower..... FN

[howie1a]

In t5hory cutting the seal back about 1/4 inch is the same as shorting the spring but if you put back a washer on each end of the spring to replace the spring length you lost due to the seal shorting would make the spring the same length it was when you starteg out but now you have a bigger air chamber. , it should give you more push , or you could replace the spring with a spring 1/4 inch longer to make up for the 1/4 inch you took off the seal. this is getting to be fun howie