Gosh, that happened to me in match. The gun made a little bunny fart. That is weird enough. I opened the cylinder, got a mess of gunpowder and then looked down and saw a bullet on the ground. It took me a few seconds to put it all together. I could pull a moon clip after shooting four rounds and see how far the bullet extended. An ACP round probably would have bound the cylinder, but the GAP isn't long enough and just falls out when they cylinder rotates. I was using Bayou and Barry's bullets. I ended up tightening the crimp (I know - it is there to take the bell out). I would push on a round against my wood workbench and when it got to the point that I could not push it in anymore, I stopped. No more problems after that. Good luck.
Steve