When I started loading 454 for my RB, my first primer choice was CCI 450. At least 1 in 10 was a missfire. Shooters on a number of other websites complain of similiar problems with CCI due to cup hardness. I changed over to Fed 205 smr primers and have fired several hundred without a missfire along with excellent accuracy. Yesterday at the range I discovered 10 rds from my early reloading--3 missfired (all 3 CCI primed). Since 454 Casull is one of the few that require sm rifle primers in a pistol cartridgethe problem seems unique to this application. I'm sharing this so that maybe some can avoid the frustration I experienced.