I got into tuning and making bits for air rifles, more specificallytheoben rapids, a few years back. A good mate and engineer taught me how to use my lathe and the science of air stripping, moderating and silencing to build very efficient shrouds and moderators. My own gun is this, a .20 rapid with a two stage carbon fibre shroud. The only part I didn't build is the block, all the internals are home built including the "rocket" valve. The lothar walther barrel is 21 1/2 inches long( turned down so it's super skinny for lightness) and ends only one inch from the start of the two stage shroud. Air is stripped from the pellet not once but twice, and all you hear is a dull phut , even when the pellets speed is in excess of 1000 feet per second. On the 110 ft range at hereward gun club just outside of Peterborough it will hit a five pence piece every time, mangling it in the process. It will shoot heavy (14.3grain) crosman prem pellets at speeds in excess of 1200 feet per second, but as the speed of sound is approx 1130 ft/sec, anything over that gets you a sonic boom( deafening believe it or not) then a pellet that flies supersonic. Supersonic is not a problem, but as it's speed decreases and it drops back into subsonic, the pellet flies all over the place giving you a shotgun scatter effect, useless for accuracy. As such I shoot at 900 ft/ sec, a good balance between power and air useage( the buddy bottle is filled to 220 bar, I think that's about 4000 psi!)
Strangely, as much as I love shooting, I hate killing anything, as such I don't hunt with it, it's just long range sniping small targets that floats my boat :-)
