Re: Evaluation of a M1A failure
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SouthTexasHill</div><div class="ubbcode-body">As several prior posters have said, check ammo and more info.
Sounds and looks like an "out of battery", bolt not locked in place, discharge of the cartridge, probably due to a high primer. Did the bolt impact the back of the receiver? If so, out of battery cartridge discharge. The fact that gases appear to have gone into the magazine also implies out of battery discharge.
I saw an out of battery discharge on an M1 Garand. It looked like the original poster's pictures, with the additional feature of the rear of the reciever was partially broken when the bolt slammed back against it. A check of the guys' reloaded ammo showed several rounds with high primers.
If a primer is too high, as the bolt pushes the cartridge forward, when the cartridge shoulder hits the forward part of the chamber and stops, the bolt can ignite the primer before the bolt rotates into the locked position.
I have run many reloads through my M1A and Garands. I am careful to not get any high primers. I have only used Lake City match brass or commercial brass, primers not crimped with either. The first time I reload, I full length size the brass and then trim it to max length less 0.010 inch. After that, I uniform the primer pockets to ensure they are the proper depth. Then, for subsequent loadings, I check the length on at least ten cases to see that they are still within limits.
When I prime them, I check that the primers are not protruding. If the primer pocket is the proper depth, the surface of the primer will be slightly below the surface of the case rim.
Mulitple discharges with one pull of the trigger is not the usual definition of a slam fire, it is usually referred to as "doubling" or "tripling" or "going full auto". In this case, the bolt locks into battery before the cartidge is fired.
FWIW and YMMV. </div></div>
Are you saying that the bolt itself ignites the primer in your scenario or the firing pin rocks foward and ignites it?
I think the safety bridge should retain the firing pin (unless it fails) until the bolt is in battery.
Im just wondering, as I am not very experienced, if it is the bolt face itself crushing the primer into firing.
Since the left side of the receiver is missing it does look like the bolt wasnt locked in battery. If it was Id think that the barrel would give first. I actually think the right side of the receiver should have given first also, as there is less steel there, and a big port to release gas pressure from