I cranked out 500 rounds of 38 special on my Square Deal B last weekend loading with 158 grain LSWC's. After I finished I checked the rounds for any defects and found that I was able to twist the bullets on a number of the rounds. I put a pretty tight crimp into the crimping groove of the bullets, so the bullets wouldn't pull out, just would turn. I was using mixed brass that I had previously tumbled. After going through the whole lot of 500, I found that the only ones with this problem were R-P cases. I assume this is Remington brass. Has anyone run into this problem?