Anyone accidentally used 300 blkout in 556?

[mark5pt56]

When I had the BO, I used Lancer mags for this very reason.

[1168]

I’ve always wanted a .300 for a super short suppressed rifle, but I have avoided it for the reasons in this thread.


What are y’all talking about with the Lancer mags?

[docsherm]

When I had the BO, I used Lancer mags for this very reason.

I only use USGI mags for my 300 BO and PMags for 5.56 for exactly that reason. That way there is no confusion about what goes where.

There are plenty of photos on BARFCOM with people doing exactly that and blowing up their uppers and barrels.

[Outlander Systems]

I’ve always wanted a .300 for a super short suppressed rifle, but I have avoided it for the reasons in this thread.


What are y’all talking about with the Lancer mags?

[mark5pt56]

I can tell you to check those Garand enbloc clips as a .270 will fire in the M1G! Yeah, it was a WTF moment, checked the rest and there was a few more scattered in. Gun was ok and I learned never to trust what' in a mag or "clip"

[mark5pt56]

I only use USGI mags for my 300 BO and PMags for 5.56 for exactly that reason. That way there is no confusion about what goes where.

There are plenty of photos on BARFCOM with people doing exactly that and blowing up their uppers and barrels.

I did use tape or the big orange rubber bands that come with the interior door hinges as we had 100's of those being destroyed in the houses. Then though the mags would be better overall.

[Tokarev]

I did an article in one of the Guns & Ammo AR15 specials-- the 6/25/2019 edition. Yep it blowed up alright. Bullet stuck in the barrel; it got reeeaall long.

We intentionally chambered a 110gr 300 BLK into a S&W MP15 chambered in 223/5.56. We weighted the rifle in place and used a piece of 550 cord to pull the trigger.

The mag blew and the upper receiver bent outward at the ejection port but the bolt and carrier held together. The extractor was destroyed but nothing else "failed" inside the gun. Other than the cartridge case, that is...

The bullet ended up an inch or two past the gas block. Yes. It got really long. Probably something like 2.5" long. Pretty amazing that the damage to the rifle wasn't more significant.

One thing of note is that it took two or three chamberings to get the bolt to close on the loaded round before our little "test." Hopefully this indicates that most 300 BLK rounds with a decent crimp will not chamber without some effort on the shooter's part...

[jsbhike]

I know someone that took a neighbor kid shooting and somehow the kid came across a .300 (he thought it was a whisper but could have been BO) laying around and stuffed it in a Sig M400 and wrecked it.

A guy I used to shoot matches with told me about a fellow club member that fired a .270 Win through a .25-06 Ruger 77 with no apparent ill effects other than sounding like cannon fire when the goof occurred.

[WillBrink]

Happened to me. It SUCKS! Someone (not me) had loaded a handful 5.56 on top of some 220 Grain 300BLK Subs in one of my magazines. I found out the hard way. Rifle was a total loss.

Did the chamber or barrel explode? What happens?

[themonk]

I use emags for blackout and any other mags for 556.