well i've been doing some more reading and i think i am looking at this gun for inspiration

http://www.spudfiles.com/forums/25-air-rifle-breech-loaded-rifled-barrel-t22941.html

but my question would be, if i replace the air chamber with a co2 bottle and regulator, would i need an expansion chamber ...

Hey everyone, first off i'm new here, so please go easy on me :o

I'm looking at building a 6mm airsoft sniper but need a bit of help. i am wanting to use either a 9oz or 12oz co2 tank for my propellant, regulated and hopefully some sort of breach to load single shots.

can you guys help point me ...