Loading... Please wait...

Like Us on Facebook!


Add to Wish List

Click the button below to add the GM-M16 20" M16 A2 5.56mm w/Ext. 1:8 twist to your wish list.

You Recently Viewed...

GM-M16 20" M16 A2 5.56mm w/Ext. 1:8 twist

Calculated at checkout

Product Description

M16A2 5.56mm, 20", 1:8 twist, 41V50 steel, weighs 2.05 lbs., fully machined and assembled with extension (M4 feed ramps), chrome line bore and chamber, .750" gas block, designed for rifle length gas system, drilled gas port, phosphate finish,button rifled, air gauged, stress relieved, muzzle thread 1/2 x 28.

Barrel is not pinned for front site.

Under "See 1 more picture" there is a detailed drawing of this barrel. 

Write your own product review

Product Reviews

Showing reviews 1-5 of 31 | Next

  1. Very nice. 5 Star Review

    Posted by on 23rd Apr 2018

    Excellent well made and fast shipping. Have not had a chance to try it yet but will soon. Thank you GM.

  2. 20” 5.56 1:8 twist 5 Star Review

    Posted by on 16th Apr 2018

    Excellent barrel. Hands down best for the money. Sub MOA accuracy with bulk ammo Will definitely buy another and recommend it 100%

  3. what i expected and more ! 5 Star Review

    Posted by on 1st Jan 2018

    I have had green mountain barrels on black powder rifles for a long time and was in need of a barrel for my new AR build . So I turned to green mountain and couldn’t be happier . I shot it today and this gun is a tack driver ...... if you are in need of a great quality barrel this is the one for you !

  4. accurate 5 Star Review

    Posted by on 31st Aug 2016

    Where the bullet meets the target is all that matters! 3/4" @ 50yds with stock iron sights and my eyes are not that great. Some of the best groups I've ever shot.

  5. Nice barrel 5 Star Review

    Posted by on 19th Aug 2016

    Barrel fit perfect. No headspace issues. Barrel has about 30 rds through it so far and is shooting sub moa at 100 yds with factory ammo. Great barrel fort the money no doubt!

Showing reviews 1-5 of 31 | Next