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GM-M20 20" 223 Wylde Chamber

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Product Description

20", 223 Wylde Chamber, 1:8 twist, 416 stainless steel, Fluted, honed, passivated, bead blasted matte finish,  Nickel Boron extension with M4 feed ramps, and has a rifle length gas block.  Weighs 2.20 lbs.

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

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Product Reviews

Showing reviews 1-5 of 54 | Next

  1. SUB MOA! 5 Star Review

    Posted by on 15th Jan 2018

    I was given a pretty low budget for an upper build for my Brother. I researched quite a few barrels and couldnt find a quality barrel for my budget, then I came across this Barrel. Hadn't heard of green mountain before so I started reading the reviews. Reviews were good and barrel looked well made, also were on sale for a little over 150 so I took a chance on it. WOW! Went through a break in period with 55 grain v-max and groups were ok, right around 1in. At 100yds. Then I went to some 69gr match ammo, which tightened up to just over .5 moa. Couldnt be happier with this barrel. It seemed to tighten up with every group. Im definitely going to have to get one of these for myself! Thanks Green Mountain for a great barrel at an excellent price!

  2. Just what I expected. 5 Star Review

    Posted by on 11th Dec 2017

    I built an AR using different parts from different companies, I won't say I compromised on anything but the vast majority of the components were near the low end of the cost scale for each. The one area where I didn't cut corners was the barrel. Green Mountain has an excellent reputation and they didn't disappoint. After a short break in / zero session at 50 yds, I moved to the 100 yd range and was rewarded with minute of angle groups with cheap FMJ ammo. I can't wait to see what it'll do with good stuff. Money well spent.

  3. Looking for value, you got it. 5 Star Review

    Posted by on 26th Nov 2017

    I have had this barrel on my SPR style Ar15 for a long while now and it has help up excessively well. With the right ammo (BlackHills 77gr, Hornady 75gr, etc) my setup will shoot sub MOA all day. I would bet if I hand loaded grouping would be tighter. Even with low quality 55gr ammo I can shoot around 2 MOA. You are not going to put bullets through the same hole at 100 yards but for everything else GM makes great barrels.

    Note: I did not do any break in as I don't believe that is necessary with a quality barrel and this barrel still shoot as accurate as it day on day one.

  4. 1ST AR build. 5 Star Review

    Posted by on 6th Sep 2017

    Recently finished my first build. When asking around about barrels GMRB was recommended to me. after reading reviews on not only the products but also the customer service and the company standing behind their products I decided to try my luck. i have 200 rounds through the rifle so far and the barrel shoots great, looks good under a free float and i have also been very impressed with the green mountain's service and follow up. highly recommend.

  5. Quality is there 5 Star Review

    Posted by on 20th Aug 2017

    I purchased this barrel over one month ago and just got the rifle together for a test at the range. I shot several rounds at 50 yards using American Eagle 55 grain fmj and then cleaned the bore. Shot a few more rounds with another cleaning and then shot Hornady 77 grain bthp match rounds. I could tell the groups tightened up using the heavier round. I had read others reviews about how this barrel seems to like the heavier rounds. I really think this barrel is going to be a keeper!

Showing reviews 1-5 of 54 | Next