Posted: Sun Oct 26, 2008 6:41 pm
hmm, maybe ill do both sides for a compromise lol
For combustion guns it's best to file down both the inside and the outside of the muzzle if you are using veggies as ammo. The outside bevel does most of the cutting, the inner bevel cuts the ammo a bit oversized for a tighter fit and increased static friction, which is desirable in a combustion gun.
In a pneumatic gun an inner bevel will somewhat reduce the need for a fast opening valve since it delays the start of ammo movement a bit and gives the valve time to open further, this can improve performance. This is partially offset by the decrease in performance caused by the greater dynamic friction that goes with the increased static friction. You can fiddle around with GGDT to see how much of an affect you will get. (GGDT only allows you to enter the static friction, it then assumes dynamic friction is half as much.)
You might consider increasing the bracing between the barrel and the chamber. As you go to heavier ammo and higher chamber pressures the recoil will increase. The recoil can put a heck of a lot of stress on your pipe elbows and the valve.
