The problem is,,,, I bought a used original contender frame, bought a 375 Winchester carbine bbl, and put it together, fits great,,,. Loaded up some ammo, went out to the range, and SNAP<SNAP<SNAP. It will fire some of the time, maybe one out of ten tries. Sometimes I can snap one a couple of times, and then the third time it will fire. In checking it, the hammer is falling all the way, not being blocked. since I have a new to me frame and bbl, I don't know which is the culprit. I have not taken another bbl or frame out to swap around. Would you agree headspace?