In a barrel for a paint-ball gun, the entrance to the bore has a chamfer. The chamfer has a smooth transition from the entrance to the bore; preferably in the form of a section of a circle or parabola. In another embodiment, the bore of the barrel has a similar smooth transition in the muzzle of the...http://www.google.com/patents/US7441557?utm_source=gb-gplus-sharePatent US7441557 - Barrel for paint-ball gun
