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August 16th, 2019

Scary Stuff — .300 Blackout Fired in a .223 Rem Barrel

.300 AAC Blackout 300 BLK kaboom accident blowup cartridge failure barrel .223 Rem 5.56
Photos and Facebook post by Tactical Rifle Shooters

Yet another .300 Blackout disaster. Unfortunately, that .300 Blackout cartridge can fit in a .223 Rem chamber. Shooting a .308-caliber bullet in .223 bore is a recipe for disaster.

.300 AAC Blackout 300 BLK kaboom accident blowup cartridge failure barrel .223 Rem 5.56

.300 AAC Blackout 300 BLK kaboom accident blowup cartridge failure barrel .223 Rem 5.56The .300 AAC Blackout aka “300 BLK”, is a compact 30-caliber cartridge designed to work in AR-15 rifles. It has a shorter cartridge case to accommodate the bigger 30-caliber bullet while still fitting in a standard AR-15 magazine. Unfortunately, that’s the danger. A careless shooter can toss a .300 Blackout cartridge in with .223 Rem rounds without noting. And because the case-head size is the same as the .223 Rem (5.56×45) the rifle’s bolt assembly will happily chamber and fire the .300 BLK round. Problem is, that forces a .308 diameter bullet down an undersized .223-caliber bore. Not good!

This images were provided by Tactical Rifle Shooters on Facebook. The message was clear: “Don’t try to run 300 Blackout in your .223/5.56mm. It won’t end well. The problem is identical rifles and identical magazines but different calibers.”

For those who MUST have a .300 Blackout, here are some things you can do:

1. Use different colored magazines for .300 Blackout vs. .223 Rem.
2. Fit all your uppers with caliber-labeled ejection port covers.
3. Mark .223 Rem upper handguards with the caliber in bright paint.
4. Mark all .300 BLK Rounds with heavy black marker.

.300 AAC Blackout 300 BLK kaboom accident blowup cartridge failure barrel .223 Rem 5.56

Comments by Folks Who Viewed these .300 Blackout Disaster Photos:

“The .300 Blackout is simply a badly-designed round. A properly-designed round would have had a feature in the shape that would have prevented cross loading in the first place.” — D. Santiago

“I almost made that mistake… I had a magazine of 300 BLK inserted in my .223/5.56 all night. Fortunately, I never pulled the trigger. Once I realized the mistake, I almost got ill. [After that incident] I no longer own a 300 BLK.” — B. Welch

“Happened to me hog hunting from a helo. Gun exploded in my face.” — B. Hood

“Fire-forming projectiles [is] so wrong in centerfire!” — M. Stres

“Had some dude come into the store the other day wanting .300 Blackout ammo to shoot in his 5.56 AR. It took 15 minutes of explaining for him to understand you got to have a .300 Blackout Upper!” — R. Williams

Permalink Bullets, Brass, Ammo, News, Tech Tip 20 Comments »
November 24th, 2018

Out-of-Battery BANG! When Round Fires Before Bolt Fully Closed

out of battery kaboom bohica 50 bmg ar15

As posted in the Calguns.net a few years back, there was a nasty out-of-battery firing incident involving a BOHICA Arms .510 DTC AR15 upper. The cause of the out-of-battery firing is not certain but it appears that the ammo was not sized properly and the firing pin may have been stuck in the extended position. As a result, the round went off before the bolt was closed with the lugs seated. In the process, the bolt handle broke off, as the bolt retracted violently, actually ending up outside the bolt raceway.

out of battery kaboom bohica 50 bmg ar15

The shooter was badly injured, with broken bones and ligament damage to his left hand and tissue damage to his right hand. The shooter was holding the rifle with his left hand near the front of the chamber where a gas vent was located. Gas and shrapnel existed the vent hole causing the severe injuries to the left hand.

From range reports, it appears that the shooter had been struggling to chamber previous rounds, and was having trouble closing the bolt. After talking with one of the rangemasters, a poster on AR15.com reported: “The guy was using new reloads that weren’t exactly fitting well into his chamber. [The shooter] was slamming the bolt handle with his palm trying to get the cases to lock in. The guy was also slamming the bolt forward full force from the rearmost position back and forth trying to ram the cases into chamber in an attempt to squeeze the rounds in so the bolt could close. Finally, on one of the attempts … the possibly stuck firing pin rams into the primer and explodes the round when he slams the bolt forward (zero lug engagement hence the KB) and shooter puts himself into a world of hurt.”

Lessons Learned — Don’t Try to Force Oversize Ammo into a Chamber
By all reports, the shooter’s ammo wasn’t fitting his chamber properly. In an effort to force the ammo into the chamber, he worked the bolt with excessive force. That MAY have caused the firing pin to extend or the hammer to fall without the trigger being pulled. One theory is that the trigger system may have been modified, allowing the hammer to fall from the force of slamming the bolt forward. Others have speculated that the firing pin may have failed to retract because the bolt handle was over-torqued — a safety issue listed in the BOHICA manual.

out of battery kaboom bohica 50 bmg ar15

Whatever caused the out-of-battery firing, it appears that improperly-sized ammo (or a poorly-cut chamber) was the root cause of the problems. If you go to a range and find your bolt does not close easily over the ammo — STOP SHOOTING — don’t try to force the issue. Disaster may result. To paraphrase Johnnie Cochran: “If the ammo doesn’t fit, it’s time to quit”.

Photos by Wildcard, originally posted on Calguns.net.

Permalink Bullets, Brass, Ammo, Shooting Skills, Tech Tip 1 Comment »