Re: Large flash holes - dangerous?
Your first paragraph shows a good understanding of the dynamics of the detonation, right down to the movement of the primer in its pocket. Like the premature detonation of a cartridge in a blowback SMG, its not appreciated by most.
Having such a thorough knowledge, I can only say to you just stick to tried and tested components. The pressures are immense, and components well tested. If you have a quantity of brass with bigger than normal flash holes, trash em! Blank or ball.