Another thing that I do stick to is: when loading for my M1A and AR I exploit 'army' primers. Particularly in the M1A. My knowing could be the 'civilian' primers are much too comfortable and promote the notorious 'slam -fires' Now I do use primer flatness as being a manual https://winchester-250-magnum-pri93603.bloggip.com/31875908/the-best-side-of-federal-large-rifle-benchrest-primers