SpudFiles

Ok, heres the deal, I am building a sniper rifle and I need help. I am thinking about making it air powered with a breech and gravity loading mechanism, and I was trying to figure out how to make it semi automatic. I was think that if I make an air chamber with a release valve where if I over fill it, it would let the extra air escape with out blowing up. Then I would hook up my air compressor to it then once it is full I would shoot, pull back the bolt, let the next golf ball fall into the barrel, close the bolt and shoot again. Any ideas on how I can improve/modify it?

The regulator on your compressor can be used to fill only to a certain psi. Or you can alternatively install a regulator on your cannon to make sure you fill at a certain level. Over filling isn't usually a problem.

Pure semi-auto's aren't child's play to get right. Have you looked at Clide's superb GB Semi?

Maybe you could do something like with a bolt that gets blown back, or forward opening the closing a valve to fill a firing chamber

a release valve where if I over fill it, it would let the extra air escape with out blowing up

Pop-off valves are nifty little things that pop open at set pressures.


You can just use a bolt-action for what you are describing to load the ammo.
For shooting, you could use a 3 way valve.
The ports of the 3 way are connected to:
1-Connected to the pilot area
2-Connected to the air supply
3-Connected to nothing
When the valve opens up the flow from 1 to 2 the gun fills up, and when you turn it so that it opens up from 1 to 3, the air feed (from 2) will be blocked off, and the gun will be piloted through port 3, thus it fires.
After firing put the valve back into the "air feeding" stance, and the gun will be refilled.