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Rainier Arms AR Mountain MOD2 5.56 NATO Barrel Up to $20.00 Off Plus Blazin' Deal w/ Free S&H — 4 models

Rainier Arms Mountain MOD2 5.56 NATO Barrel, 12.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-125-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 14.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-145-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 16in, 1/2x28, Mid Len, Black, Medium, RAB-CMV-556-16-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 10.5in, 1/2x28, Carbine Len, Black, Small, RAB-CMV-556-105-C-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 12.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-125-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 12.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-125-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 12.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-125-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 12.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-125-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 12.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-125-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 14.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-145-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 14.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-145-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 14.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-145-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 14.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-145-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 14.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-145-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 16in, 1/2x28, Mid Len, Black, Medium, RAB-CMV-556-16-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 16in, 1/2x28, Mid Len, Black, Medium, RAB-CMV-556-16-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 16in, 1/2x28, Mid Len, Black, Medium, RAB-CMV-556-16-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 16in, 1/2x28, Mid Len, Black, Medium, RAB-CMV-556-16-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 16in, 1/2x28, Mid Len, Black, Medium, RAB-CMV-556-16-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 16in, 1/2x28, Mid Len, Black, Medium, RAB-CMV-556-16-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 10.5in, 1/2x28, Carbine Len, Black, Small, RAB-CMV-556-105-C-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 10.5in, 1/2x28, Carbine Len, Black, Small, RAB-CMV-556-105-C-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 10.5in, 1/2x28, Carbine Len, Black, Small, RAB-CMV-556-105-C-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 10.5in, 1/2x28, Carbine Len, Black, Small, RAB-CMV-556-105-C-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 10.5in, 1/2x28, Carbine Len, Black, Small, RAB-CMV-556-105-C-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 10.5in, 1/2x28, Carbine Len, Black, Small, RAB-CMV-556-105-C-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 12.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-125-M-HF-BLK
1 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 12.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-125-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 14.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-145-M-HF-BLK
2 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 14.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-145-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 16in, 1/2x28, Mid Len, Black, Medium, RAB-CMV-556-16-M-HF-BLK
3 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 16in, 1/2x28, Mid Len, Black, Medium, RAB-CMV-556-16-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 10.5in, 1/2x28, Carbine Len, Black, Small, RAB-CMV-556-105-C-HF-BLK
4 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 10.5in, 1/2x28, Carbine Len, Black, Small, RAB-CMV-556-105-C-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 12.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-125-M-HF-BLK
5 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 12.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-125-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 12.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-125-M-HF-BLK
6 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 12.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-125-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 12.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-125-M-HF-BLK
7 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 12.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-125-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 12.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-125-M-HF-BLK
8 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 12.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-125-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 12.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-125-M-HF-BLK
9 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 12.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-125-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 14.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-145-M-HF-BLK
10 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 14.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-145-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 14.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-145-M-HF-BLK
11 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 14.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-145-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 14.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-145-M-HF-BLK
12 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 14.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-145-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 14.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-145-M-HF-BLK
13 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 14.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-145-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 14.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-145-M-HF-BLK
14 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 14.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-145-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 16in, 1/2x28, Mid Len, Black, Medium, RAB-CMV-556-16-M-HF-BLK
15 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 16in, 1/2x28, Mid Len, Black, Medium, RAB-CMV-556-16-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 16in, 1/2x28, Mid Len, Black, Medium, RAB-CMV-556-16-M-HF-BLK
16 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 16in, 1/2x28, Mid Len, Black, Medium, RAB-CMV-556-16-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 16in, 1/2x28, Mid Len, Black, Medium, RAB-CMV-556-16-M-HF-BLK
17 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 16in, 1/2x28, Mid Len, Black, Medium, RAB-CMV-556-16-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 16in, 1/2x28, Mid Len, Black, Medium, RAB-CMV-556-16-M-HF-BLK
18 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 16in, 1/2x28, Mid Len, Black, Medium, RAB-CMV-556-16-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 16in, 1/2x28, Mid Len, Black, Medium, RAB-CMV-556-16-M-HF-BLK
19 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 16in, 1/2x28, Mid Len, Black, Medium, RAB-CMV-556-16-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 16in, 1/2x28, Mid Len, Black, Medium, RAB-CMV-556-16-M-HF-BLK
20 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 16in, 1/2x28, Mid Len, Black, Medium, RAB-CMV-556-16-M-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 10.5in, 1/2x28, Carbine Len, Black, Small, RAB-CMV-556-105-C-HF-BLK
21 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 10.5in, 1/2x28, Carbine Len, Black, Small, RAB-CMV-556-105-C-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 10.5in, 1/2x28, Carbine Len, Black, Small, RAB-CMV-556-105-C-HF-BLK
22 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 10.5in, 1/2x28, Carbine Len, Black, Small, RAB-CMV-556-105-C-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 10.5in, 1/2x28, Carbine Len, Black, Small, RAB-CMV-556-105-C-HF-BLK
23 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 10.5in, 1/2x28, Carbine Len, Black, Small, RAB-CMV-556-105-C-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 10.5in, 1/2x28, Carbine Len, Black, Small, RAB-CMV-556-105-C-HF-BLK
24 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 10.5in, 1/2x28, Carbine Len, Black, Small, RAB-CMV-556-105-C-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 10.5in, 1/2x28, Carbine Len, Black, Small, RAB-CMV-556-105-C-HF-BLK
25 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 10.5in, 1/2x28, Carbine Len, Black, Small, RAB-CMV-556-105-C-HF-BLK
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 10.5in, 1/2x28, Carbine Len, Black, Small, RAB-CMV-556-105-C-HF-BLK
26 of 26 images
Rainier Arms Mountain MOD2 5.56 NATO Barrel, 10.5in, 1/2x28, Carbine Len, Black, Small, RAB-CMV-556-105-C-HF-BLK

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Questions & Answers
Is this chrome lined?

No they are nitrided

by Trebor Cash, Verified Owner, February 6, 2026
View All Q&A You Have a Question? Ask!
Customer Reviews
Helpful Positive Review
Sub MOA barrell by Praise the Lord and Pass the Ammo, Verified Owner, March 12, 2023
I purchased the Ranier Arms AR Mountain Mod 2 5.56 barrell. To begin with, the barrell looks harty with its heavy contour and linear fluting, but thats only where thr barrell begins to shine. After assembly I put the barrell to the test. It consisten...
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4/4 found this helpful
Read 1 Review
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Product Info for Rainier Arms AR Mountain MOD2 5.56 NATO Barrel

Allow us to reintroduce ourselves. We have brought back our Mountain Series of barrels for those of you who want the accuracy you expect from Rainier Arms in a nearly indestructible package. These barrels are made out of 4150 CMV and nitrided as well. That means these barrels will take anything you can throw at them. They are meant to be shot, and shot a lot. The half-fluted profile maximizes heat dissipation and helps reduce weight.image

Specifications for Rainier Arms AR Mountain MOD2 5.56 NATO Barrel:

Manufacturer: Rainier Arms
Color: Black
Fabric/Material: 4150 CMV Steel
Caliber: 5.56x45mm NATO
Barrel Profile: M4
Gas Block Journal Size-Diameter: .750 in
Barrel Twist Rate: 1-7
Flutes: Yes
Gun Make: AR Platform
Gun Model: AR-15
Condition: New
Firearms Threads Per Inch: 1/2x28

Package Contents:

  • Rainier Arms Mountain MOD2 5.56 NATO Barrel

What firearm models does the manufacturer say Rainier Arms AR Mountain MOD2 5.56 NATO Barrel is compatible with?

The manufacturer says that Rainier Arms AR Mountain MOD2 5.56 NATO Barrel is compatible with AR-15

Rainier Arms AR Mountain MOD2 5.56 NATO Barrel Orderable Models

List of Orderable Models

  • Rainier Arms Mountain MOD2 5.56 NATO Barrel, 12.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-125-M-HF-BLK , MPN: RAB-CMV-556-125-M-HF-BLK , UPC: 744985350858 , Code: 4ZM-ATB-CPO21-RAB-CMV-556-125-M-HF-BLK
  • Rainier Arms Mountain MOD2 5.56 NATO Barrel, 14.5in, 1/2x28, Mid Len, Black, Small, RAB-CMV-556-145-M-HF-BLK , MPN: RAB-CMV-556-145-M-HF-BLK , UPC: 744985350865 , Code: 4ZM-ATB-CPO21-RAB-CMV-556-145-M-HF-BLK
  • Rainier Arms Mountain MOD2 5.56 NATO Barrel, 16in, 1/2x28, Mid Len, Black, Medium, RAB-CMV-556-16-M-HF-BLK , MPN: RAB-CMV-556-16-M-HF-BLK , UPC: 744985350872 , Code: 4ZM-ATB-CPO21-RAB-CMV-556-16-M-HF-BLK
  • Rainier Arms Mountain MOD2 5.56 NATO Barrel, 10.5in, 1/2x28, Carbine Len, Black, Small, RAB-CMV-556-105-C-HF-BLK , MPN: RAB-CMV-556-105-C-HF-BLK , UPC: 744985350841 , Code: 4ZM-ATB-CPO21-RAB-CMV-556-105-C-HF-BLK
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Last updated 2026-07-07 UTC.