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Questions & Answers
What is the twist rate for both .308 cal barrels?

I believe that 1:10 and 1:12 are the most common twist rates for .308 caliber barrel.

by JD, Verified Owner, February 11, 2021
How much does the medium profile 20" barrel weigh? Expert Answer

CMMG does not state the weight of the CMMG, Inc 308 Win Barrel Sub-Assembly. I recommend contacting CMMG for that information.

by Hunter, Gear Expert, April 13, 2023
Customer Reviews
Most Recent Reviews
Good, accurate shorty .308 barrel. by JB83, Verified Owner, July 10, 2025
I have heard both bad and good about CMMG barrels and I only have this one to test. That said, I have liked it so far. Seems accurate. Have yet to bench zero... Came pre-dimpled for the gas block. I love that it has mid-length gas... that's going to ...
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Read 1 Review
Color:
Silver
Finish:
Stainless Steel
Caliber:
.308 Winchester
Barrel Length:
18 in
Barrel Profile:
Heavy Taper
Gas System Length:
Rifle Length
Gas Block Journal Size-Diameter:
.936 in
Barrel Twist Rate:
1-10
Flutes:
No
Gun Model:
AR-10
Condition:
New
Firearms Threads Per Inch:
5/8x24

Code: 2CM-ATB-308WINBRL-38DCC0A

MPN: 38DCC0A

UPC: 815835016320

List: $299.95Save 10%
$269.99

Product Info for CMMG, Inc 308 Win Barrel Sub-Assembly

This CMMG 308 Win Barrel Sub-Assembly is the perfect raw material to craft your custom MK3 upper group. CMMG constructed these Rifle Barrels with a properly installed barrel extension so that you can save even more time by avoiding the extra hassle of installing a barrel after the fact. This CMMG 308 Rifle Barrel Sub-Assembly comes headspaced for a reliable build, and the 5/8x24 threads allow for the installation of a variety of accessories you may need down the road. Make sure you pick up a CMMG 308 Barrel Sub-Assembly w/ Extension if you're looking to build your own MK3 upper group.image

Specifications for CMMG, Inc 308 Win Barrel Sub-Assembly:

Manufacturer: CMMG
Color: Silver
Finish: Stainless Steel
Fabric/Material: 416 Stainless Steel
Caliber: .308 Winchester
Barrel Length: 18 in
Barrel Profile: Heavy Taper
Gas System Length: Rifle Length
Gas Block Journal Size-Diameter: .936 in
Barrel Twist Rate: 1-10
Flutes: No
Gun Model: AR-10
Condition: New
Firearms Threads Per Inch: 5/8x24

Package Contents:

  • CMMG, Inc 308 Win Barrel Sub-Assembly

CMMG, Inc 308 Win Barrel Sub-Assembly Orderable Models

List of Orderable Models

  • CMMG, Inc Barrel Sub-Assembly, Heavy Taper, 308 Win, 18in, 416SS, 38DCC0A , MPN: 38DCC0A , UPC: 815835016320 , Code: 2CM-ATB-308WINBRL-38DCC0A

CMMG, Inc 308 Win Barrel Sub-Assembly Unavailable & Discontinued Models

List of Unorderable Models

  • CMMG, Inc Barrel Sub-Assembly, Mediun Taper Profile, 308 Win, 12.5in, 416SS, Salt Bath Nitride, 38D920A , MPN: 38D920A , UPC: 815835016351 , Code: 2CM-ATB-308WINBRL-38D920A
  • DEMO, CMMG, Inc Barrel Sub-Assembly, Heavy Taper, 308 Win, 18in, 416SS, 38DCC0A , MPN: 38DCC0A-DEMO , Code: 2CM-ATB-308WINBRL-38DCC0A-DEMO
  • CMMG, Inc Barrel Sub-Assembly, Medium Taper, 308 Win, 16.1in, 416SS, Salt Bath Nitride, 38DEA7A , MPN: 38DEA7A , UPC: 815835016337 , Code: 2CM-ATB-308WINBRL-38DEA7A
  • DEMO, CMMG, Inc Barrel Sub-Assembly, Medium Taper, 308 Win, 16.1in, 416SS, Salt Bath Nitride, 38DEA7A , MPN: 38DEA7A-DEMO , Code: 2CM-ATB-308WINBRL-38DEA7A-DEMO
  • DEMO, CMMG, Inc Barrel Sub-Assembly, Mediun Taper Profile, 308 Win, 12.5in, 416SS, Salt Bath Nitride, 38D920A , MPN: 38D920A-DEMO , Code: 2CM-ATB-308WINBRL-38D920A-DEMO
  • CMMG, Inc Barrel Sub-Assembly, Medium Taper, 308 Win, 20in, 416SS, Salt Bath Nitride, 38DDA0C , MPN: 38DDA0C , UPC: 816422026821 , Code: 2CM-ATB-308WINBRL-38DDA0C
  • CMMG, Inc Barrel Sub-Assembly, Heavy Taper, 308 Win, 24in, 416SS, Salt Bath Nitride, 38D4B0C , MPN: 38D4B0C , UPC: 816422026838 , Code: 2CM-ATB-308WINBRL-38D4B0C
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Last updated 2026-06-28 UTC.