AR-15/M16 300 BLK BARRELS Reviews & Ratings

Direct replacement for the standard .223/5.56mm barrel converts your AR-15 to the high-performance 300 AAC Blackout (300BLK) cartridge. The 300 AAC lets you upgrade your rifle to 7.62 x 39 ballistics, while retaining the standard AR-15/M16 bolt, carrier, and magazine at its full capacity, with no additional modifications. 1-7" rifling accepts bullet weights from 110 gr to 220 gr, and 5/8"-24 muzzle threads accept popular AR-.308 flash suppressors and muzzle brakes. Three models available, 16", 12.5" and 8.2" long and treated inside and out with CMMG’s "Wasp" nitriding process for outstanding resistance to wear and corrosion. 16" barrel has the gas port in the standard position for use with all M4-length gas systems and supersonic ammunition. 12.5" & 8.2" barrels have the gas port positioned for use with pistol-length gas systems.

SPECS: Hardened 4140 chrome-moly steel, Wasp nitride finish, matte black .750" O.D. at gas port.5/8-24 muzzle threads.

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3 Stars

2 Stars

1 Stars

14%

Reviews Summary

Customers have mixed experiences with the AR-15/M16 300 BLK barrels. Many praise the accuracy and ease of installation, with a few indicating flawless performance. However, some encountered issues like dull crowns and headspace concerns. Customer service responses were mentioned positively, but repair timelines caused frustration. Overall, while quality control is variable, many were satisfied with the barrels' performance.

What Reviewers Are Saying

Product Quality

60%

The quality of the barrels received mixed reviews. While many customers were impressed with fit, finish, and performance, others experienced issues with crown cuts and headspacing, suggesting inconsistency in manufacturing quality.

Accuracy and Performance

70%

Many reviews highlight the barrels' accuracy as a standout feature, with users achieving impressive groupings even with various loads. Positive performance reports contribute to satisfaction, with some citing flawless operation during testing.

Customer Service

40%

Customer responses towards service were largely positive, with CMMG offering repairs for defective products. However, delays in repair times created frustration for some users who felt it negatively impacted their experience.

Installation and Compatibility

30%

Most users found installation straightforward, with parts aligning well. Issues were reported by a few regarding gas port alignment affecting the performance, indicating that precision during installation is critical.

Value for Money

45%

The affordability of the barrels impressed many reviewers, leading to a perception of good value for the performance received. Several customers noted they achieved competitive accuracy levels without breaking the bank.

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CMMG makes a quality product

I just ordered this 12.5" 300 Blackout barrel however I have one other 300 16" build and a 5.56 pistol with a 12.5" CMMG barrel. My 16" Blackout is a heck of an accurate shooter hampered only by me and my hand loads using pulled 147 gr .308 bullets as plinkers. The barrels are well finished in matt Nitride that cleans quickly and rifled 1/7 which many say is the optimum for the 300. I have shot approximately 400 rounds through the Blackout and easily a thousand in the 5.56 without incident . I will build an upper with the 12.5" 300 Blackout barrel and case with both caliber uppers, the pistol lower and extra magazines.

Awesome barrel

I was looking for a lighter weight barrel for a carbine project, CMMG makes this one at a weight of only 1.8# and coupled with a Midwest Industries 10" lightweight kemod rail the rifle turned out to be all I expected. Sight in with iron sights took five shots and from that point my old eyes could easily keep it in the black. This rifle will be tested on Texas hogs soon.

Working well for my build

Had some FTF in the beginning, but they've seem to have settled down on the second test. Overall I'm satisfied with the product and cannot complain. I noticed by posting through the 300blktlk forum that the gas port hole is not ground like it should be in order to provide a proper match with the gas block. I also had to make sure my gas block was PERFECTLY centered, otherwise there wasn't enough gas to chamber the next round. (short stroking) Honestly, when I do my next one I will not be using a CMMG barrel. Wilson is only a few bucks more.

great barrel

The barrel was great. I love the finish and fit. It is ballanced well too. I did have a few "hiccups" so to speak. Still working through it, it may be a break in issue. So far I've only shot about 20 handloads of 110 grain Nosler BT. I had a few issues with the rounds fully chambering feeding from the magazine, it wouldn't fully chamber the round. I could eject the round and load it one at a time, and it works fine. That is the reason for the 4 stars. The accuracy is very good so far, still working on the hand loads and T & E and I haven't stretched it out yet. The recoil was very light for a 30 caliber round.