Case Failure
I believe Mr Tooley is right on the money. I have seen this kind of case failure before, looks like a brass lamination.
One of the things that occurs with small capacity cartridges & heavy bullets is a sharper pressure curve resulting in higher primer pocket pressures than occur with the same cartridge & lighter bullets even when the peak pressure is similar. This puts more load on the head section of these cartridge/bullet combination. this why blanked primers occur in such rifles when using heavy bullets & do not occur in the same rifle when using light bullets. This is what has led to the now quite common practice of reducing firing pin diameter & bushing the firing pin hole to suit in these rifles. This rifle was on the verge of primer blanking. I do not think excessive pressure was the cause. .223 brass is very strong in the web due to the design of the rifles for which it was designed to be fired in (AR15's). when a case head separation occurs in a .223, it will occur half way along the case from the head, not as close to the head as in other cartridges due to the longer web taper of the .223 case.
Glad no one was seriously hurt, good modern actions do handle this kind of incident rather well.
Just my observations & Aussie 2 cents worth.
Keith H.
I believe Mr Tooley is right on the money. I have seen this kind of case failure before, looks like a brass lamination.
One of the things that occurs with small capacity cartridges & heavy bullets is a sharper pressure curve resulting in higher primer pocket pressures than occur with the same cartridge & lighter bullets even when the peak pressure is similar. This puts more load on the head section of these cartridge/bullet combination. this why blanked primers occur in such rifles when using heavy bullets & do not occur in the same rifle when using light bullets. This is what has led to the now quite common practice of reducing firing pin diameter & bushing the firing pin hole to suit in these rifles. This rifle was on the verge of primer blanking. I do not think excessive pressure was the cause. .223 brass is very strong in the web due to the design of the rifles for which it was designed to be fired in (AR15's). when a case head separation occurs in a .223, it will occur half way along the case from the head, not as close to the head as in other cartridges due to the longer web taper of the .223 case.
Glad no one was seriously hurt, good modern actions do handle this kind of incident rather well.
Just my observations & Aussie 2 cents worth.
Keith H.