Daniel Defense 16″ Cold Hammer Forged Barrel, .300 Blackout, 1:8 Twist, S2W Profile, Carbine-Length, with Low Profile Gas Block

Product Description

The Daniel Defense 16″ Cold Hammer Forged Barrel in .300 Blackout is a 1:8 twist, S2W-profile barrel on a carbine-length gas system in the low profile gas block configuration, weighing 2.29 lbs and threaded 5/8×24 TPI at the muzzle.

Daniel Defense describes this barrel as being for shooters who want the benefits .300 Blackout offers in an AR-15 build, including its ability to cycle subsonic rounds suppressed. That is the cartridge’s defining advantage: a 5.56-pattern rifle that can fire heavy subsonic projectiles with a can attached and still cycle reliably, without the receiver changes a different platform would need.

The 1:8 twist is chosen for the heavy bullets .300 Blackout uses, and 16 inches is the length that makes the cartridge work: it clears the federal rifle minimum without a pinned muzzle device, and it gives supersonic loads enough barrel to reach useful velocity while remaining short enough that the rifle handles well with a suppressor hanging off the end.

Key Facts

• Brand: Daniel Defense
• Model: 16″ 300 Blackout, Carbine, 1:8, S2W
• Manufacturer Part Number: 36-116-08063
• Caliber: 300 BLK
• Barrel Length: 16″
• Twist Rate: 1:8
• Barrel Profile: S2W (Daniel Defense proprietary Heavy Barrel)
• Gas System: Carbine Length
• Manufacturing Process: Cold Hammer Forged
• Material: 4150 Chrome Moly Vanadium (CMV) steel
• Bore Finish: Chrome lined
• Exterior Finish: Mil-Spec Heavy Phosphate
• Muzzle Thread: 5/8×24 TPI
• Diameter at Gas Port: .750″
• Barrel Extension: A4
• Barrel Weight: 2.29 lbs
• Barrel Configuration: With low profile gas block

Muzzle threads: 5/8×24, not 1/2×28

This is the single most important fitment detail on this barrel. The muzzle is threaded 5/8×24 TPI, not the 1/2×28 used on Daniel Defense’s 5.56 barrels. Daniel Defense makes the point directly: many of its 5.56 rifles use 1/2×28 muzzle threads, while 300 Blackout and many 7.62-pattern rifles commonly use 5/8×24, and you should check the product page for your exact model before ordering a muzzle device, suppressor mount or adapter.

Building a suppressed .300 Blackout upper

Beyond the barrel you need a .300 Blackout bolt, a carbine-length gas tube, a .750-inch gas block and magazines you are willing to dedicate to the cartridge. Marking .300 Blackout magazines clearly matters, because a .300 Blackout round can chamber in a 5.56 barrel with dangerous results.

Pick a .30-calibre can from our suppressors, add a matching bolt from our bolt carrier groups and charging handles, or browse ammunition for subsonic loads.

Ordering from Western Sport in Roanoke, TX

Western Sport is a Daniel Defense master dealer and a licensed FFL and SOT in Roanoke, Texas, in business since 2007 with a gunsmith on site. Suppressed .300 Blackout builds are a favourite here, and we can handle both the upper and the Form 4 side. Call 817-393-4000.

Frequently Asked Questions

Q: What muzzle thread does this .300 Blackout barrel use?

A: 5/8×24 TPI, not the 1/2×28 found on Daniel Defense’s 5.56 barrels. Daniel Defense states that 300 Blackout and many 7.62-pattern rifles commonly use 5/8×24, and advises checking the product page for your model before ordering a device or mount. Your 5.56 muzzle devices will not fit this barrel.

Q: Will this barrel cycle subsonic ammunition suppressed?

A: Daniel Defense describes this barrel as being for shooters who want the benefits .300 Blackout offers, including its ability to cycle subsonic rounds suppressed. The carbine-length gas system on a 16″ barrel is the standard arrangement for that. An adjustable gas block, which this low profile configuration leaves easy to fit, helps fine-tune it.

Q: Do I need a different bolt for .300 Blackout?

A: You need a .300 Blackout bolt; the cartridge uses the same case head as 5.56 but bolts are sold specifically for it and mixing parts is not worth the risk. The barrel extension here is A4, the standard AR-15 pattern, so the receiver, carrier and charging handle are unchanged.

Q: Why 1:8 twist instead of 1:7?

A: Because .300 Blackout uses heavier, larger-diameter bullets than 5.56, and 1:8 is the twist Daniel Defense specifies for this barrel to stabilise them, including the heavy subsonic projectiles the cartridge is known for. Twist rate is matched to bullet weight and diameter, so a 5.56 twist figure does not transfer across.

Q: Can I use my 5.56 magazines?

A: Standard AR-15 magazines feed .300 Blackout, but you should dedicate and clearly mark magazines for it. A .300 Blackout cartridge can chamber in a 5.56 barrel with dangerous consequences, so keeping the ammunition and magazines physically separated from your 5.56 kit is a genuine safety practice, not a formality.

Q: What does this 16″ .300 Blackout barrel weigh?

A: Daniel Defense lists 2.29 lbs for this 16″ .300 Blackout S2W profile barrel. That reflects the heavy Strength to Weight contour, which adds thermal capacity and stiffness that suit a suppressed gun shooting volume subsonic ammunition. Add your gas block, gas tube, barrel nut, handguard and mount for a total upper weight.

Additional information