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GM-B5 17" Gunsmith Edition 300 Blackout 1:7 twist Unfinished Barrel

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Product Description

 300 black out, 1:7 tweist, 17" long, 41V50 steel, weighs 3 lbs., chambered in 300 black out, button rifled, stress relieved, air gauged, chrome line bore and chamber, phosphate extension, gunsmith edition blank.


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Product Reviews

  1. Excellent Shooter 5 Star Review

    Posted by on 15th Nov 2018

    I'm so pleased with the accuracy of this chambered blank I had to write a second review on it.
    I'm running it on a minimalist carbine with a full A2 stock, ALG enhanced Mil spec trigger, and troy sights, every part is Mil spec but the Magpul grip and forend. It is as a 80% build.
    It shoots so well it is all I'm interested in using for deer hunting and pest control on my farm. Using Hornady 110grn V-Max Black Ammo, you site it in 3.5 inches high at 100 yards, it hits zero at 200 yards. With 10 rd Pmags, it is a super light weight handling carbine. Simple. Reliable. Rugged.
    We got kill orders from F&G for deer in the cornfields. Filled 10 tags, plus a doe on an early Doe season for land owners. 1 shot 1 kill every time. Hit them in the chest DRT, any angle. It hits like a 44mag rifle at 50 yards, regardless of distance. Great barrel. There is no way I could claim this without the crazy iron sight accuracy of this chambered blank.

    It isn't a fluke, cause I used a .556 chambered blank on another build, same set up but with an Aimpoint Patrol red dot. I've never grouped so tight with a .556 AR.
    The confidence factor is off the charts when you can build a weapon which is so brutally dead nuts on. I'm talking real world real use.
    If you have any question in your mind, chuck it. Get yourself one of these chambered blanks, take your time, get it zeroed on your lathe, have yourself a match grade barrel with military grade chrome lining at a super good price.
    Next is their .308 chambered blank and a dead nuts accurate AR10.

  2. Great Barrel 4 Star Review

    Posted by on 8th Feb 2018

    I only gave the barrel 4 stars because I haven't shot it yet. This is my first barrel from Green Mountain and so far I'm very pleased. This Gunsmith edition was easy to machine and made it easy to build a bolt action ar with no gas system. The price was right and shipping is fairly priced and very fast. The 1-7 twist is great for stabilizing heavier grain bullets. This barrel is a win, win in my opinion.

  3. GMRB Quality 5 Star Review

    Posted by on 8th May 2017

    Like all the barrel blanks from Green Mountain I have used, this 300AAC AR-15 chambered blank is 1st rate in every respect. Plus you get an excellent price that leaves you with room to make a decent penny and offer it at a reasonable price.
    Not to mention the excellent customer service, and shipping.
    Win-Win all around.
    You all should be proud at GMRB, you guys have a great thing going.

    As a gunsmith machinist, I find these blanks are easy turning and consistent results are achieved, and because of that it is simple to achieve .0005 or less runout on chambering, crowning, and threading. And that is key to the level of accuracy I am achieving using GM barrel blanks.
    This particular product though, is on the next level. You are able to produce any number of configurations easily and not have to go through the time and process of a mil spec chrome lining job.
    And these are 1-7 twist blanks, which is perfect for stabilizing the 200+ grain subsonic rounds.
    Top shelf all the way.