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GM-M41 12.5" 300 Blackout AR15 barrel 1:7 5R twist

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Product Description

300 blackout, 1:7 5R Twist, 12.5" long, 41V50 steel, weighs 1.2 lbs., AR15 barrel with a button rifled, stress relieved, air gauged.

Features include a Pistol Length, .750” diameter gas system, a chrome lined bore and chamber, phosphate finish, Fluted taper, assembled extension with M4 feed ramps and 5/8-24 muzzle threads.

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Product Reviews

  1. Really unbeatable barrel. Great quality and price. 5 Star Review

    Posted by on 17th Dec 2019

    Ordered it easily. It shipped fast. The quality is outstanding. Came prenotched for the pin on gas block. There’s only one other 12.5” 300bl barrel on the market and it’s at least a hundred more. I can’t fathom it being and better quality.. this was a great buy.

  2. great quality barrel 5 Star Review

    Posted by on 21st Oct 2019

    Very well made quality barrel.
    Great profile too. Going to make a great hunting rifle

  3. Awesome barrel in hard to find length 5 Star Review

    Posted by on 19th Sep 2019

    I received this barrel in record time; Green Mountain has crazy fast shipping times.

    The barrel itself is awesome and has worked out perfectly for an SBR build. I ended up using a Geissele gas block (I used the two set screws but did not use the cross-roll pin...the cut out on the barrel was designed with a different gas block in mind). This barrel is extremely durable but also quite light. With a lightweight Midwest Industries handguard, the rifle is very well balanced (probably one of the most comfortable ARs I own).

    I haven't done extensive long range (as long range as you get with 300 blackout anyways) accuracy testing yet, but have had zero function issues.

    I highly recommend this barrel if you're looking to set up a 300 blackout build in this length.

  4. another greeen mountain great 5 Star Review

    Posted by on 30th May 2017

    I was bit hesitant with no reviews but this barrel had all the attributes I was looking for. 1/7, 5R, lightweight, attributes you would normally find in a much more expensive barrel. Don't care for the slight taper but it doesn't seem to affect accuracy. With a red dot and bad vision I was able to get right under 1 moa at 100 yds with American eagle 150 grain fmjs. The fluting and finish is top notch as usual with green mountain barrels. If your looking for a 300 blk barrel that's under 16" and can still give you 2300-2400 fps with supers accurately this is your barrel. If I could change one thing I would tell green mountain to get rid of the taper and keep it a consistent diameter beyond the gas block. Further testing with chrono and 120 grain supers to come. Thanks again green mountain for a great product