bk40, question? You have loaded the 454 with SMALL rifle primer's, I may be wrong, I don't own a 454, but I thought it was made to use a large pistol/rifle primer. I am not calling you on the carpet, I am just asking a question, I am new here and you sound like you know what you are talking about. I have used small pistol primers in the .30 carbine with a Ruger Blackhawk, just because it made for a more accurete load. And I have used large rifle primers in the .44 mag in place of mag LP primers for the same reason. I have always reduced loads and worked up with the crony for help.