Back around 1980, when I was in the Army, a buddy of mine bought a satin nickeled Combat Commander (remember those?) in , he thought, .45ACP. The slide was marked .45, it had a .45 barrel in it, the slide stop was correct, but the breech face was milled for the 9mm/.38Super. Needless to say, it wouldn't work well. His father's buddy, and his father, too, were somewhat kitchen table gunsmiths, and they finally figured out what was wrong, and corrected the situation. It turned into a pretty good gun, but there was some serious headscratching going on for quite awhile. As noted earlier, I would sure look at the breechface, and maybe, the extractor, which might be the wrong size, and see what that does for you. A very firm grip might also help!