At the range this week I was testing loads in my .45 Colt SAA clone (Uberti). Shooting cast 452-255 RF powder coated ahead of 6.5 grains of Unique (starting load). CCI 300 primers in new Starline cases. I shot 9 rounds and the cylinder started jamming up on the second cylinder. Inspection showed primers backing out in shot cases, that is why the cylinder is trying to jam up. In 30+ years of hand loading my own ammunition, I've never had primers back out before. The loads did seem a little snappy but I didn't experience 44 mag type of recoil at all. I've never hand loaded the .45 Colt cartridge before, most of my big bore revolvers are .44 mag. My load of 6.5 grains of Unique for a 255 grain cast bullet is my starting load going up to 8.0 grains at the other end of the spectrum. Seems like I'm going to have to disassemble those loads now. I am really surprised by this and I'm curious if anyone has had a similar experience in this cartridge. This load was intended to be a target load, easy shooting. Maybe I need to go to a faster powder for this cartridge. I have Bullseye, Red Dot, 700X, Green Dot and AA#5 on hand I could switch to. To repeat, using NEW cartridge cases Starline headstamp and CCI#300 primers. Thanks all...JJ