CMMG .308 Barrel 4140 Nitride Mid-length - 12.5"

Manufactured by CMMG
SKU: 38D920A
MPN: 38D920A
Manufactured by CMMG
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NOTE: This barrel is less than 16” in length and is intended for use in legal short-barreled rifle builds. Other configurations may violate Federal law.

Build a compact AR-10 with the CMMG 12.5” .308 barrel. It is machined from 4140 chrome moly steel with a medium tapered profile to reduce weight without sacrificing rigidity. It features a salt bath Nitride finish inside and out for long lasting durability and a mid-length gas system for reliable function. The .750” gas block shelf is compatible with a wide range, so you can throw on an adjustable gas block to fine tune your .308 pistol. The 5/8x24 threads allow you to choose your favorite .30 caliber muzzle device or suppressor for the ultimate build. Whether you are building an AR-10 pistol or even SBR, this CMMG barrel won’t disappoint.

  • 12.5″
  • Medium Taper Profile
  • 4140 Chrome Moly Steel
  • Salt Bath Nitride Finish Inside and Out
  • 1:10 Twist
  • 308 WIN Chamber (also accepts 7.62×51 NATO)
  • Threaded 5/8-24
  • Mid-Length Gas Port
  • .750″ Gas Journal

A leading manufacturer of AR-15 rifles, kits, and accessories, CMMG Inc. was established in 2002. Constantly pushing the edge, CMMG strives to develop and improve bringing you a product lineup that is second to none.
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Barrel CoatingSalt Bath Nitride
Barrel ContourMedium Taper
Barrel Length12.5
Barrel LiningSalt Bath Nitride
Barrel Material4140 Chrome Moly Steel
Caliber Gauge.308 Win
Feed RampsM4
Gas Seat Diameter.750
Gas System LengthMid-Length
Thread Pattern5/8 X 24
Twist Rate1:10

WARNING: This Product can expose you to chemicals which is known to state of California to cause Cancer and Reproductive Harm. For more information, see

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