300 Blackout fired in 5.56 rifle KABOOM

[firelieu596]

Reported to have happened at a gun range in Monroe, GA. I did not think the 300 could be chambered in a 5.56 rifle and it should not have fired out of battery.



https://www.facebook.com/photo.php?fbid ... =1&theater

[talonxracer]

The 300blk is well known to be able to be chambered and fired in a 556 chambered rifle. There has been several instances of negligence and this has occured, it is ENTIRELY user error!!!!!!

The bullet is merely set back into the case as the BCG goes into battery creating a hand grenade.

You will find several threads about marking 300blk vrs 556 mags.

[Hardrockshot]

If the rifle had not gone to battery had did the round go off? Open breach discharge. Looks like the the bolt went forward, closed up tight.........

[jc10311]

I am absolutely convinced that it's possible to chamber a 300 BLK round in a 5.56 gun and fire it. I did an experiment a while back using an inert (no primer or powder) 300 BLK round to see what happened. As a result of this I make absolutely sure that I never have a magazine full of 300 BLK on the table when I have a 5.56 gun out. I probably won't make the mistake, but the guys shooting with me may not pay attention when they shoot my gun.

http://youtu.be/Dq2TjenPWmQ

[gunnyart]

my method is to only use 20rd Pmags for blackout and 30rd'ers for 5.56

[AR-300]

I don't own a 223 upper so no worries here.
FYI the bolt will close and lock on a 300
so it is not a OOB KB,
just a swage 308 to 223 KB

[Jim Timber]

I use color coding - all 300blk is foliage green, and black and tan are reserved for .223. The only time I muddy those is when I'm the only one shooting since I haven't been able to acquire reasonably priced mags to fill my blackout quota. In time, that will change and it'll be a hard rule even for me.

[jeephipwr]

My 556 mags are aluminum with magpul followers and floorplates. My 300 mags are pmags

[the tick]

Didn't even know that was possible. Good to know.

[Rifleman]

If the rifle had not gone to battery had did the round go off? Open breach discharge. Looks like the the bolt went forward, closed up tight.........

That's what happens. The expanding gas has to go somewhere and the extractor cutout channels it. The results are pictured above. The probability of occurrence is related to the user's competence.