Thread: What happened here?

Cases over FL sized (sloppy) usually result in flat primers which is usually mistaken for a pressure issue. Primers not seated deep enough (as per 7x64) will cause misfires although generally reloaders tend to seat them too deep ie crush them. I cut my pockets to 120.5 thou and then preload the primers by 1 thou. You can roughly check the pocket depths with a vernier although I use a depth mic. Different brands of primers are also different in their thickness/depth so some will seat further onto the pockets. Firing pin protrusion can cause an issue as well although unlikely if you haven't had the problem the past.