Curl- I use Fed 215's mainly in the BP ctg. guns now. I have used them in the .358 Norma and saw no difference betweent hem and the CCI250's. The Feds are supposed to have a longer flash time to better ignite huge powder charges. I know they have delivered slightly better accuracy in the Sharps with black powder for me. As to their use in normal magnum rounds, I doubt they'd show any benefit. When changing primers, one should always reduce the charge a grain or two and test for changes in case had measurement indicating pressure changes.