Quote Originally Posted by Pressingonward View Post
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Out of the ~100 rounds I shot yesterday, I had one fail-to-fire on a brass cased PPU FMJ round. It has a tiny punch mark on the primer instead of the nice big dimple on all of the cases that fired correctly. I've read about light primer strikes, I'm guessing that's what this is? I don't quite understand how I could get such a tiny punch mark on this round - wouldn't the firing pin leave a big dimple whether or not the primer ignited?
sometimes just the action of charging the round into battery leaves a tiny dimple, the AR-15 firing pin is free-floating in the bolt, inertia allows it to contact the primer going into battery.