Oversize flash hole/case rupture

[br1111]

Just a spitball here: Is is possible for the flash hole to be big enough to allow detonation of the powder at the base of the case rather than ignition?

I had a buddy chambered a round of 6 ppc and it went in tight and blew the case got him right below the left eyeball (right bolt left port).I carried him to the hospital.one of the larger pieces of brass went in under the eye ricocheted off a bone behind the eye and ended up very close to the optic nerve. he had surgery and wound up ok. the round he chambered was to thick for the neck diameter and pinched the bullet in the neck and that caused it to blow. what ever caused it for your bullet to get pinched and not release obviously is unknown, but I bet you that was the cause.

 

[Dave Marshall]

Just a spitball here: Is is possible for the flash hole to be big enough to allow detonation of the powder at the base of the case rather than ignition?

The US Army did some studies on flash holes. For the most part, the size of the flash hole doesn’t matter.

 

[divingin]

Just a spitball here: Is is possible for the flash hole to be big enough to allow detonation of the powder at the base of the case rather than ignition?

Powder doesn't detonate. At ambient pressure, it burns slowly. At higher pressure (as in a chambered round) it burns faster.

Overpressure scenarios come from powder burning into gases faster than the pressure can be relieved (no surprise here, as that's what pushes the bullet out of the barrel), but building excess pressure so rapidly that the containment fails. No detonation anywhere other than the primer.