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Choosing the Right 300 Blackout Barrel for Your 300 Blackout

The 300 Blackout is an incredibly versatile round. It can act as a high-velocity, high-grain power puncher. It can tone things down with a suppressor, but remain supersonic – and lethal at medium distance. It can choose subsonic loads without a suppressor and smash cinder blocks at 100 meters. And, it can be whisper-quiet with a suppressor and subsonic loads.

But making your 300 BLK do all these magic tricks – or perfecting some while eschewing others – means investing in the right kit. Let’s help you out with today’s topic: Choosing the right 300 Blackout barrel for your 300 Blackout build!

Rifle Barrels

If you’re opting for a rifle barrel, chances are you’re working at longer distances and you’re enjoying supersonic loads more often than subsonic. But within this realm of medium-distance, supersonic shooting, you’ll need to decide: Do you commit to sheer accuracy and spring for a longer, heavier – and less maneuverable – barrel? Or do you compromise on a shorter profile that’s lighter in weight, but perhaps less accurate?

300 Blackout 16” SS M4 Profile Barrel (1:8 Twist, 416R Steel)

This shiny piece of steel is one of the most accurate 300 Blackout barrels available on the market. Its 416R stainless steel affords impressive accuracy. The 416 base steel this barrel’s made from boasts excellent machinability – meaning more structured and consistent rifling lands and grooves.

Its “R” designator guarantees lower sulfur content, making for a smoother, denser barrel surface. Thanks to its M4 profile it is still lighter in weight than a bull barrel, so you won’t necessarily have to feel stressed while carrying or shouldering your rifle. Lastly, its 1:8 twist rate is excellent for those heavier rounds.

300 Blackout 14.5” Contoured AR-15 Barrel (1:7 Twist, 4150 Chromoly)

This bad boy is a customer favorite thanks to its compact profile, 1 MOA-capable accuracy, and 4150 Chromoly steel boasting a hardness rating of RC 28 to 32. It features a pistol-length gas system and its shorter length is perfect for building a hyper-accurate 300 BLK SBR. This one’s also a favorite because adding any muzzle device and pinning it permanently will make it a legal rifle barrel.

Its 1:7 twist rate favors lighter rounds while its parkerized, mil-spec finish blends in perfectly with any upper and lower receiver. At 1.66 pounds, it’s a perfect lightweight barrel that’s still rugged as Hell.

Pistol Barrels

300 BLK-chambered pistol barrels follow a similar philosophy as their rifle counterparts: Do you go longer, heavier, and more accurate for range day? Or do you remain compact, lightweight, and zip-quick, ready for close quarters?

300 Blackout 10.5” Heavy SS AR-15 Pistol Barrel (1:7 twist, 416R Steel)

Our 10.5” SS 300 BLK Barrel is a heavy-hitter in the realm of accurized 300 BLK pistols. Featuring the same 416R stainless as its rifle brethren, this barrel’s 1:7 twist-rate rifling guarantees MOA accuracy with lighter grain rounds and peak performance from any sub- or supersonic loads.

300 Blackout 7.5” Heavy AR-15 Pistol Barrel (1:7 twist, 4150 Chromoly)

You guessed it – we’ve got a pistol version of our popular parkerized, 4150 rifle barrel! This short 7.5” bull boy is the golden tick for building a 300 BLK pistol that’s perfect for close quarters and quick maneuvers. Its 1:7 twist-rate heavy barrel provides the best possible accuracy with those light loads in a short profile, while its 5/8×24 threaded muzzle begs for a suppressor. At 2.5 pounds and at such a short length, some shooters report this profile and weight providing the perfect balance and stability needed for tight shot groups.

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 300-blackoutupper, 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.


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