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GM-M51 M4 Barrel Assembly

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Product Description

For a Limited Time, the NEW GM-M51!

A 16” M4 barrel, 5.56 caliber with a 1:7 RH Twist. It’s already assembled with an A2 Front sight Base, Post, Detent, and Spring, a Handguard cap, and Barrel Nut. The GM-M51 sports a Carbine Gas length, M4 Feed ramps, Chrome lined bore and Phosphate exterior coating, and of course, All the Quality and Performance you expect from GMRB. Quantities are limited.

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Product Reviews

  1. Wow! 5 Star Review

    Posted by on 22nd Oct 2017

    I bought this barrel the 2nd week it came out and have about 500 rounds of green tip 62g federal through it. I shoot anywhere from 50-150 yards and the groups a just as tight as my bcm barrel. I’m super happy with it and will forever go with Green Mountain Barrels!

  2. The best barrels you can buy without having sell a kidney. 5 Star Review

    Posted by on 9th Oct 2017

    This is the 3rd barrel I've bought and once again I'm not disappointed. They have a great life span and accurate as anything else.

  3. Great Barrel 4 Star Review

    Posted by on 13th Sep 2017

    A great barrel for my M4 build. It's worked great. All the specs were what I wanted. The only thing I wish was different is the FSB. It's an A2 FSB, not "F" marked. I knew this, and still thought the barrel was a great buy. I do wish going forward, they would have an "F" marked FSB, as that is the standard for a carbine build. Still, love the barrel.

  4. Quality Barrel 5 Star Review

    Posted by on 18th Aug 2017

    I knew of GM's reputation for quality barrels, so when I began my AR build, I checked GM first and was surprised to find the GM-M51. A 16" M4 barrel 1/7 twist and chrome lined already assembled, I couldn't order it fast enough.
    Shipping was fast(Shipped the following day) and I had the barrel installed in less than 20 minutes, it was my my first build. I've only been to the range once so far, but the groups are tight and I'm a happy GM customer.

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