Green Mountain GM-M8 16" Chrome Lined Mid-Length 1/8 5.56 Barrel
16" mid length gas system, 5.56mm NATO 1:8 twist, 41V50, chromed bore and chamber, phosphate finish, button rifled, thermo stress relieved, precision air gauged, gas port, assembled with M4 extension with M4 feed ramps, muzzle thread 1/2 x 28.
.750 at gas port.
Weighs 1.9 lbs.
Very accurate good quality.
Posted by JS on Apr 9th 2017
Most impressed with speed of shipping and top notch customer service of Wolf Hollow. This is a good quality barrel also
Posted by Unknown on Feb 24th 2017
I wanted a standard chrome-lined barrel with mid-length gas for an all-around use AR, but I didn't want to pay a lot for one. This barrel had all the specs I was looking for, and the price was excellent. I knew Green Mountain had a great reputation for Ruger 10/22 barrels but I couldn't find much about their AR barrels. So I rolled the dice and ordered one and so far it has done exactly what I wanted it to do. Granted, it doesn't make match ammo out of mil-spec 55 grain FMJ loads, but it shoots them no worse than any other AR I have. It shoots my Nosler 55 grain Ballistic Tip and 77 grain Nosler HPBT handloads very well, and that was my biggest concern.
The only concern I had with this barrel is that it is slightly overgassed. I failed to measure the gas port before I assembled the upper, so I don't know the actual size of the port. However an H-buffer has fixed the problem, and if I decide to suppress it I can just use an adjustable gas block. I know that most manufacturers these days use a larger port so that it will be reliable with inexpensive low-powered .223 loads that are so prevalent, so this is not unique to Green Mountain.
Overall I'm impressed with this barrel especially considering the price. For an all-around use AR that will be with me in my truck or on the rack of my ATV this barrel worked out perfectly.
Posted by Vernon W. on Jan 5th 2017
Searched forever for a barrel I wanted and stumbled across this on sale. Shipping was faster than it could track it. As far as shooting ive not got all my parts in for my build but I hope so soon. Packing was was great overall looks are perfect clean threads and shiny bore and mine was stamped 5.56 NATO 1/8.
Posted by John A. on Nov 21st 2016
Barrel was shipped fast and packed nicely. Fit and finish is excellent with clean cut threads and a nice looking bore. Accuracy is very good, makes sub groups @100yds with 62 grain xm223sp1. Overall I'm very happy with this barrel and would recommend a green mt barrel to anyone.