CMMG AR-15 Barrel, 16.1″ MT 4140CM SBN, 300 BLK

MSRP: $189.95


A .300 blackout barrel for AR-15s

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The CMMG 300 AAC Blackout Barrel features 1 in 7″ twist rifling and a carbine length gas system. The muzzle is threaded 5/8″-24 for use with muzzle brakes, flash suppressors, or sound suppressors. Gas block and gas tube not included.

The barrel is composed of Chrome Moly Steel and finished inside and out with CMMG’s durable salt bath nitride finish. The unique treatment applied to the barrel surface-hardens the metal, extending barrel service life by reducing friction in the bore and lessening bore surface wear. It produces an extremely hard, slick surface on steel that resists carbon adhesion and increases corrosion resistance, making for easier cleaning and maintenance. Nitriding converts the steel’s surface without any build-up, retaining all of the benefits of traditional chrome lining without suffering the accuracy degradation commonly encountered due to uneven application of chrome inside the barrel’s bore.


– Chamber: 300 AAC Blackout
– Length: 16″
– Material: Chrome Moly Steel
– Contour: Medium, Stepped
– Twist Rate: 1 in 7″
– Chrome Lined: No
– Finish: Salt Bath Nitride
– M4 Feed Ramps: Yes
– Muzzle Thread Pattern: 5/8″-24
– Gas Port Location: Carbine
– Exterior Diameter at Gas Port: 0.750″
– Suitable for use with Subsonic or Supersonic loads, either Suppressed or Unsuppressed

Manufacturer's SKU: 30D120A

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Additional information

SKU: 189675

Weight2 lbs
Dimensions18.25 x 1.75 x 1.75 in


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WARNING: This product contains a chemical known to the State of California to cause cancer.

Also, drinking water and breathing heavily has been known to cause cancer by the state of California.

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