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CMMG, Inc 5.56x45mm NATO Barrel Sub-Assembly Up to 11% Off w/ Free Shipping — 6 models

CMMG, Inc Barrel Sub-Assm, 16.1in LT 4140CM SBN, 5.56mm, 55D470B
CMMG, Inc Barrel Sub-Assm, 16.1in LT 4140CM SBN, 5.56mm, 55D470B
CMMG, Inc Barrel Sub-Assembly, 16.1in. MT 416SS, 5.56mm 55D590A
CMMG, Inc 5.56x45mm NATO Mk4 Barrel Sub Assembly, 12.5in, MR 4140CM SBN, 5.56mm, 55DDF0A
CMMG, Inc Barrel AR15, 5.56, 16in, M4 LE, 55DE10A
CMMG, Inc Barrel Sub-Assembly, 16.1in. MT 4140CM SBN, 5.56mm 55DC70A
CMMG, Inc Barrel Sub-Assembly, 5.56x45mm, 18 inch, Medium Taper, Mid-Length Gas, 1-7 Twist, 1/2-28 Thread, 416SS, SBN, Black, 55DFD0C
CMMG, Inc 5.56x45mm NATO Mk4 Barrel Sub Assembly, 12.5in, MR 4140CM SBN, 5.56mm, 55DDF0A
CMMG, Inc Barrel AR15, 5.56, 16in, M4 LE, 55DE10A
CMMG, Inc Barrel Sub-Assm, 16.1in LT 4140CM SBN, 5.56mm, 55D470B
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CMMG, Inc Barrel Sub-Assm, 16.1in LT 4140CM SBN, 5.56mm, 55D470B
CMMG, Inc Barrel Sub-Assm, 16.1in LT 4140CM SBN, 5.56mm, 55D470B
2 of 9 images
CMMG, Inc Barrel Sub-Assm, 16.1in LT 4140CM SBN, 5.56mm, 55D470B
CMMG, Inc Barrel Sub-Assembly, 16.1in. MT 416SS, 5.56mm 55D590A
3 of 9 images
CMMG, Inc Barrel Sub-Assembly, 16.1in. MT 416SS, 5.56mm 55D590A
CMMG, Inc 5.56x45mm NATO Mk4 Barrel Sub Assembly, 12.5in, MR 4140CM SBN, 5.56mm, 55DDF0A
4 of 9 images
CMMG, Inc 5.56x45mm NATO Mk4 Barrel Sub Assembly, 12.5in, MR 4140CM SBN, 5.56mm, 55DDF0A
CMMG, Inc Barrel AR15, 5.56, 16in, M4 LE, 55DE10A
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CMMG, Inc Barrel AR15, 5.56, 16in, M4 LE, 55DE10A
CMMG, Inc Barrel Sub-Assembly, 16.1in. MT 4140CM SBN, 5.56mm 55DC70A
6 of 9 images
CMMG, Inc Barrel Sub-Assembly, 16.1in. MT 4140CM SBN, 5.56mm 55DC70A
CMMG, Inc Barrel Sub-Assembly, 5.56x45mm, 18 inch, Medium Taper, Mid-Length Gas, 1-7 Twist, 1/2-28 Thread, 416SS, SBN, Black, 55DFD0C
7 of 9 images
CMMG, Inc Barrel Sub-Assembly, 5.56x45mm, 18 inch, Medium Taper, Mid-Length Gas, 1-7 Twist, 1/2-28 Thread, 416SS, SBN, Black, 55DFD0C
CMMG, Inc 5.56x45mm NATO Mk4 Barrel Sub Assembly, 12.5in, MR 4140CM SBN, 5.56mm, 55DDF0A
8 of 9 images
CMMG, Inc 5.56x45mm NATO Mk4 Barrel Sub Assembly, 12.5in, MR 4140CM SBN, 5.56mm, 55DDF0A
CMMG, Inc Barrel AR15, 5.56, 16in, M4 LE, 55DE10A
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CMMG, Inc Barrel AR15, 5.56, 16in, M4 LE, 55DE10A

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Questions & Answers
Do we know what kind of feed ramps this barrel has. Expert Answer

The CMMG, Inc 5.56x45mm NATO Barrel Sub-Assembly have M4 Extensions.

by Hunter, Gear Expert, February 15, 2023
Is the barrel dimpled? Expert Answer

The CMMG, Inc 5.56x45mm NATO Barrel Sub-Assembly are not dimpled from the manufacturer.

by Hunter, Gear Expert, July 6, 2022
View All Q&A You Have a Question? Ask!
Customer Reviews
Most Recent Reviews
CMMG barrel by Ron, February 24, 2021
I have not been able to do any rea testing with it yet. However, it's made out of the materials I was looking for. I think it will provide lots of good service and am looking forward to doing much testing with it. Once I finish the build which I am n...
Read More...
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6 Models Available
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Product Info for CMMG, Inc 5.56x45mm NATO Barrel Sub-Assembly

Perfect for building your custom AR15 upper group. Comes with properly installed M4 barrel extension. All barrel sub-assemblies are properly headspaced.image

Features of CMMG, Inc 5.56x45mm Nato Mk4 Barrel Sub Assembly - 12.5inch Mr 4140cm Sbn, 5.56mm:

  • 12.5"
  • Multi Role Profile
  • 4140 Chrome Moly
  • Salt Bath Nitride Finish inside and out
  • 1:7 Twist
  • 5.56×45 NATO Chamber
  • Threaded 1/2-28
  • Carbine length gas port
  • .750" Gas Journal

Package Contents:

  • CMMG, Inc 5.56x45mm Nato Mk4 Barrel Sub Assembly - 12.5inch Mr 4140cm Sbn, 5.56mm

Specifications for CMMG, Inc 5.56x45mm NATO Barrel Sub-Assembly:

Manufacturer: CMMG
Caliber: 5.56x45mm NATO
Barrel Twist Rate: 1-7
Flutes: No
Gun Model: AR-15
Included Accessories: Standard
Condition: New
Gun Type: Rifle
Firearms Threads Per Inch: 1/2x28

Package Contents:

  • CMMG, Inc 5.56x45mm NATO Barrel Sub-Assembly

What firearm models does the manufacturer say CMMG, Inc 5.56x45mm NATO Barrel Sub-Assembly is compatible with?

The manufacturer suggests that CMMG, Inc 5.56x45mm NATO Barrel Sub-Assembly is compatible with AR-15

CMMG, Inc 5.56x45mm NATO Barrel Sub-Assembly Orderable Models

List of Orderable Models

  • CMMG, Inc Barrel Sub-Assembly, Medium Taper, 5.56mm, 16.1in, 416SS, 55D590A , MPN: 55D590A , UPC: 815835016160 , Code: 2CM-ATB-CNBT-55D590A
  • CMMG, Inc Barrel Sub-Assembly, Multi Role Profile, 5.56mm, 12.5in, 4140CM, Salt Bath Nitride, 55DDF0A , MPN: 55DDF0A , UPC: 815835016221 , Code: 2CM-ATB-CNBT-CMMG55DDF0A
  • CMMG, Inc Barrel Sub-Assembly, Medium Taper, 5.56mm, 18in, 416SS, Salt Bath Nitride, 55DFD0C , MPN: 55DFD0C , UPC: 816422026876 , Code: 2CM-ATB-CNBT-55DFD0C
  • CMMG, Inc Barrel Sub-Assembly, Light Taper, 5.56mm, 16.1in, 4140CM, Salt Bath Nitride, 55D470B , MPN: 55D470B , UPC: 815835018102 , Code: 2CM-ATB-CNBT-55D470B
  • CMMG, Inc Barrel Sub-Assembly, Medium Taper, 5.56mm, 16.1in, 4140CM, Salt Bath Nitride, 55DC70A , MPN: 55DC70A , UPC: 815835016153 , Code: 2CM-ATB-CNBT-55DC70A
  • CMMG, Inc Barrel Sub-Assembly, M4 Profile, 5.56mm, 16.1in, 4140CM, Salt Bath Nitride, 55DE10A , MPN: 55DE10A , UPC: 815835014067 , Code: 2CM-ATB-CNBT-55DE10A

CMMG, Inc 5.56x45mm NATO Barrel Sub-Assembly Unavailable & Discontinued Models

List of Unorderable Models

  • CMMG, Inc Barrel Sub-Assembly, Heavy Taper, 5.56mm, 16.1in, 4140CM, Salt Bath Nitride, 55D780A , MPN: 55D780A , UPC: 815835016191 , Code: 2CM-ATB-CNBT-55D780A
  • CMMG, Inc Barrel Sub-Assembly, Bull Profile, 5.56mm, 16.1in, 4140CM, Salt Bath Nitride, 55DAC0B , MPN: 55DAC0B , UPC: 815835018119 , Code: 2CM-ATB-CNBT-55DAC0B
  • DEMO, CMMG, Inc Barrel Sub-Assembly, Bull Profile, 5.56mm, 16.1in, 4140CM, Salt Bath Nitride, 55DAC0B , MPN: 55DAC0B-DEMO , Code: 2CM-ATB-CNBT-55DAC0B-DEMO
  • CMMG, Inc Barrel Sub-Assembly, Bull Profile, 5.56mm, 18in, 416SS, 55D630B , MPN: 55D630B , UPC: 815835018126 , Code: 2CM-ATB-CNBT-55D630B
  • CMMG, Inc Barrel Sub-Assembly, Medium Taper, 5.56mm, 18in, 416SS, 55D660A , MPN: 55D660A , UPC: 815835016184 , Code: 2CM-ATB-CNBT-55D660A
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Last updated 2026-10-01 UTC.