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We are a national retailer of individual components and not all products depicted on this website are legal in every state. Shipping of various products found on this website are prohibited to some states (such as California, Connecticut, New Jersey, New York, Pennsylvania, and Washington). The information, pictures, text or products presented on this website are not a representation by us, and should not be understood by you, that any product or completed firearm is legal to assemble or own in your state of residence. We encourage each and every builder to perform their own research about the state and federal laws that apply to them. It is your responsibility to understand the law and we encourage you to consult with an attorney or your local ATF representative.

300 Blackout vs. Body Armor and Bulletproof Glass

Posted by 80-lower on Oct 24th 2019

300 Blackout vs. Body Armor and Bulletproof Glass

Every time a new “gee whizz” rifle cartridge comes out, the curiosities about it can do begin to mount. One of the template questions is, “can it penetrate body armor”? While this curiosity is a novelty for most, 300 BLK serves its purpose among military folks and operators, so it’s worthy of analysis.

Is 300 BLK Effective After Penetration?

We’ll preface this with an obvious clarification: Any centerfire rifle shooting supersonic cartridges will cut through level IIIA soft body armor without much ado. But what happens once it passes through the body armor itself?

Thanks to popular gun review and testing aficionado TWANGnBANG (who you should definitely watch if you enjoy these sorts of tests), we have a definitive example of the trauma and penetration that 300 BLK is capable of, once passing through an NIJ-certified Level IIIA soft plate:

(Courtesy of TWANGnBANG)

Here we see that the cartridge – A Barnes VOR-TX 125-grain JHP with polymer tip, traveling around 2,335 feet per second – managed to inflict. The round broke clean through the soft armor and penetrated around 13” of ballistic gel. Upon impact, it managed a maximum expansion of around 0.6” with a minimum expansion of .4”.

Although TWANGnBANG found two of the round’s four jacket petals didn’t expand, some fragmentation did occur. This is certainly a devastating wound channel, even with just partial expansion. Mind you, this is a supersonic load.

What About Subsonic?

300 BLK 220-grainers traveling around 1,000 feet per second are pretty devastating, too. Enough so that, according to field tests of Remington’s 300 BLK loads, they can punch through bulletproof glass. If you’re a lover of pistols and other things that are subsonic, you might be scratching your head on this one. After all, bulletproof glass has been shown to repeatedly stop pistol rounds with higher grains and the same velocities.

Remington’s 220-grain, subsonic 300 BLK defeats bulletproof glass (Courtesy of The Wound Channel)

But it’s all in the aerodynamics of the round itself. Take a big, nasty .451 Detonics Magnum with a 395-grain bullet as an example that this writer tested himself. It travels at around 1,000 feet per second, the same as Remington’s subsonic 300 Blackout. But it doesn’t get through bulletproof glass (it’s been tested, too), and that’s because it’s a wide, flat round – just like most other pistol rounds.

Dual-Purpose with a Magazine Swap

But take the long, thin, arrow-shaped 300 BLK that weighs a bit less and travels the same, and you’ll end up with a round that can be suppressed and still defeat IIIA stuff, be it soft armor or glass. That’s huge for the special operations and SWAT community – teams that have previously relied on submachine guns when they need something compact and suppressed.

If over-penetration is ever a concern, they can switch out for supersonic loads and reduce the risk of collateral damage. If the environmental concerns change and a quiet approach is needed, there is no need to change the arsenal or the gear – just swap magazines and thread the muzzle. That’s the beauty of 300 BLK in a threat-contact situation, and it’s one reason why some operators enjoy this round.

DISCLAIMER: If you are new to the world of DIY gun building, you likely have a lot of questions and rightfully so. It’s an area that has a lot of questions that, without the correct answers, could have some serious implications. At 80-lower.com, we are by no means providing this content on our website to serve as legal advice or legal counsel. We encourage each and every builder to perform their own research around their respective State laws as well as educating themselves on the Federal laws. When performing your own research, please be sure that you are getting your information from a reliable source.

We are a national retailer of individual components and not all products depicted on this website are legal in every state. Shipping of various products found on this website are prohibited to some states (such as California, Connecticut, District of Columbia, New Jersey, New York, Rhode Island, and Washington). The information, pictures, text or products presented on this website are not a representation by us, and should not be understood by you, that any product or completed firearm is legal to assemble or own in your state of residence. We encourage each and every builder to perform their own research about the state and federal laws that apply to them. It is your responsibility to understand the law and we encourage you to consult with an attorney or your local ATF representative.