Discover the perfect 7.62×35 mm barrel for your AR build with our selection of 300BLK barrels. Choose various lengths from 7 to 16 inches, plus some available with flutes and different finishes to create your dream barrel. Made from 4150 Chrome Moly Vanadium steel and finished with a corrosion-resistant nitride coating or comes in Stainless Steel, these 300 blackout barrels are built to last. Find the right barrel length and install it on your AR-15 Upper configuration. Shop and Save While Building the Firearm of Your Dreams.

300 Blackout Barrels

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Choosing a 300 Blackout Barrel

Barrel length and gas system

300 BLK is efficient in short barrels, so 7.5"–10.5" pistol builds are common with pistol/carbine gas. It uses the standard AR-15 bolt and magazines — only the barrel changes the caliber.

Twist rate

1:7 or 1:8 — the fast twist stabilizes the heavy 200gr+ subsonic bullets 300 BLK is known for, as well as supersonic loads.

Profile, steel, and thread

4150 CMV nitride or stainless; some fluted to shed weight. Muzzle thread is 5/8x24 for 300 BLK muzzle devices and suppressors.

Frequently Asked Questions

Why is 300 Blackout good in a short barrel?

It reaches near-full velocity from a 7.5–10.5" barrel, where 5.56 falls off — ideal for compact and suppressed builds.

What thread pitch are these?

5/8x24. (Keep 300 BLK separate from 5.56 ammo — it can chamber in a 5.56 barrel with dangerous results.)

Do you need an FFL to buy a barrel?

No — a barrel ships without an FFL.