Pictures: 300 Blackout in a 5,56 Barrel 16″

Eric B
by Eric B

ESG Gunworks LLC is a Class 2 manufacturer formed in 2008 by three police officers. They are located in Texas and specialize in building AR-15 and AR-10 style rifles according to the customer’s needs.

One of their customer brought in a rifle made by them, an ESG 5.56 mm where the customer had shot a 300 Blackout through the barrel, with some devastating results.

Luckily only the rifle was damaged. Everything from the Bolt Carrier Group, barrel, upper receiver, lower receiver to the charging handle shows signs of the catastrophe.

A picture of the barrel cutaway was posted on their Facebook, and the picture went viral. TFB then managed to get pictures of the of the upper and lower, which you can see below.

Below: It looks like there is a hole through the metal, but not sure.

It seems it’s pretty common to (try) to shoot 300 BLK through 5,56 barrels, or vice versa.

Bolt Carrier beyond repair.

That’s a bit wider than normal.

The lower had some serious damage. That is not going to bend back by itself.

Ed VandenBerg at VandenBerg Custom did the cutaway of the barrel.

As you can see the 300 (7,62 mm) bullet almost made it all the way through the barrel. There was only about 1-2 inches missing for it to clear and exit.

This was a 16″ barrel, so it got pretty far. I must say I’m impressed.

Thanks a lot to ESG Gunworks LLC for letting us use your pictures, I really hope they can serve as a warning for others.

Having both 556 and 300 BLK rifles I really fear doing this mistake as well, and will look into ways of avoiding this in a future article.

Below is a picture I just took. Hint – has nothing to do with the ESEE Model 5 knife.

I also noticed that ESG do Machine Gun Rentals. That’s pretty cool.

Eric B
Eric B

Ex-Arctic Ranger. Competitive practical shooter and hunter with a European focus. Always ready to increase my collection of modern semi-automatics, optics, thermals and suppressors. TCCC Certified. Occasionaly seen in a 6x6 Bug Out Vehicle, always with a big smile.

More by Eric B

Join the conversation
2 of 108 comments
  • Sunshine_Shooter Sunshine_Shooter on Nov 19, 2018

    This is why I don't own 5.56 and .300BLK. One or the other, because we all make mistakes.

  • Wymon Watson Wymon Watson on Nov 19, 2018

    I have the best solution of all, I have my .30 cal ar in 7.62x39, ammo is way cheaper than bo, and I'm 100% sure I will never accidentally chamber a round in one of my 5.56 uppers.