Not saying this is your problem just want to point out at one time I had a USFA start locking up and everyone said it was primers backing out. The thing was the same ammo worked in all kinds of other SAA pistols with no issue. Chased the primer backing out for months trying to figure out what was going on because everyone I asked said that was what was going on. Well, it was not primers backing out. In fact primers always back out and then are reseated by recoil. What it turned out to be was the recoil plate had recessed just enough for the primer to catch on it. I was new to the sport at the time and everyone I asked never once said look to see what the primer is catching on for it to drag. Since then I always look to see what it is dragging on first because that is usually what is going on. Hope this helps!