Something which i do stick with is: when loading for my M1A and AR I take advantage of 'military services' primers. Especially in the M1A. My knowledge is the 'civilian' primers are too comfortable and boost the notorious 'slam -fires' Now I do use primer flatness to be a manual https://winchester-primers-uk82604.answerblogs.com/32027858/facts-about-federal-large-pistol-primers-no-150-revealed