[rsobin]

I can’t think of a powder you can double load in 223 or 5.56 and not overflow the case. Something else is going on here.

[Afterguard]

Agreed. I use 23.5 grains of Reloader15 in .223 cases and it fills them up to the top without making it a compressed load. My guess would be squib obstruction followed by a full power load. I don’t even want to think about a deliberate explosive off the shelf round.

[Ruy Dias de Bivar]

***I can’t think of a powder you can double load in 223 or 5.56 and not overflow the case.***

How true! Someone probably grabbed the BULLSEYE instead of the IMR 4895 or IMR 4350.

[riverrunner]

I can think of a lot of powders you can more then double load in a 223.

But they are not normal rifle powders.

A case full of any of the pistol/shotgun powders out there would take most rifles apart.

[jboot]

A friend of mine blew up a nice Inland M1 Carbine because he tumbled some dirty old ammo before firing it. He left it in the vibe tumbler for days and the powder in the cases was ground down almost as fine as talc. Those cases sure came up pretty, though. ;-)