I've had no problem hand-priming with CCI, but don't run 'em through a Dillon RL550. They don't feed so dependably, for some reason, according to Dillon. I tried them this weekend, and, of course, I have a major jam in the primer tube to clean up. Of course, this proves little-- it's anectdotal, and the primers were (no kidding) made in the '70s or earlier!