[Hellgate]

Occasionally there is a residual lip along the edge of the chambers caused by machining the face of the cylinder. This shaves a ring but the edge of the chamber is slightly smaller than the rest of the chamber and the ball is a loose fit. I've heard it being called "ball creep". The cure for this STD is to slightly chamfer the mouths of the chambers to remove the lip and the balls should be shaved a bit less but stick to the chamber walls by friction fit. If you bevel too much the balls will not be shaved but will swage into the chambers and still stay put. It's an easy fix and even I have successfully performed the cure.