October 30, 2018
By Steve Gash
CMMG’s MkW ANVIL AR-15-style rifle has a lot of features and is chambered for a host of popular and unique cartridges. A recent addition is a nice carbine chambered for the 6.5 Grendel cartridge, a terrific little round that hits way above its weight class.
The ANVIL is a noteworthy achievement in firearms design and not just another AR. CMMG says the ANVIL is “ultra durable,” and a peek at the design shows why. The ANVIL is a midsized platform built to handle cartridges with a larger case diameter and higher bolt thrust than the 5.56 NATO. The ANVIL has what CMMG calls its “POWERBOLT,” which allows the rifle to utilize a modified AR-10 (i.e., .308-sized) bolt for increased strength and durability. This is important for larger cartridges. The Grendel case’s rim is 0.438 inch in diameter; the 5.56 case mikes 0.378 inch. For the 6.5 Grendel to be housed in a standard-sized AR-15, material of the bolt proper would have to be milled out to make room for the larger case head. This would result in a rather thin and fragile boltface. The POWERBOLT allows the ANVIL to comfortably handle the 6.5 Grendel as well as other larger cartridges.
In addition, the ANVIL is built on an AR-10-size frame with the upper receiver shortened by 0.75 inch. This design feature minimizes weight and makes for a better-handling rifle. Significantly, although the frame is based on the AR-10, the magazine well on the lower receiver is designed to accept standard AR-15 magazines.
The heart of any rifle is its barrel. The ANVIL tube is made of 416 stainless steel with a 1:8 twist. The muzzle is threaded 5/8x24. Barrel length is 16.1 inches, not counting the muzzle brake.
The handguard is CMMG’s RKM 15-inch KeyMod, and it has plenty of accessory attachment points. The pistol grip is Magpul and has a trapdoor cap. The stock is CRT Carbine and is adjustable for length of pull.
The 6.5 Grendel ANVIL comes in three variations, and complete uppers are also available. All rifles have 16.1-inch barrels, and there are two pistol versions that have 12.5-inch barrels.
The 6.5 Grendel has been my favorite AR cartridge since its inception. Its 0.264-inch-diameter bullets are not only ballistically superior to .224-caliber ones, but also the larger case holds enough powder to give bullets sufficient velocity for serious downrange power and a delightfully flat trajectory. And the recoil doesn’t knock your hat off. It shoots sleek 100- to 130-grain 6.5mm bullets at velocities all out of proportion to its case size, and downrange velocities and retained energy make it a proven performer on game. I have taken game as large as a 236-pound aoudad ram with the Grendel, and it was one shot, down and out.
Overall accuracy of the ANVIL was excellent, averaging 0.79 inch at 100 yards. The tightest groups were made with Alexander Arms’s load with the Barnes 120-grain TSX, which averaged 0.53 inch; velocity was 2,378 fps. The fastest load was also from Alexander Arms. Loaded with the Berger 100-grain HPBT, it registered 2,630 fps.
In short, the new MkW ANVIL chambered for 6.5 Grendel was delightful, if unsurprising. It is a tough-as-nails AR engineered with extra-robust parts that enhance its reliability and longevity.