CMMG Barrel Review (2024 UPDATE) Everything You Need To Know

CMMG Barrel Review
Alfred Mendoza

Choosing the right barrel is one of the most critical decisions you will make in a gun build since the barrel you choose will impact accuracy more than any other component. In this CMMG barrel review, we’ll see if CMMG can deliver on accuracy, aesthetics, and innovation.

CMMG is manufacturer specializing in accessories like conversion kits, handguards, muzzle devices, and barrels for pistols and rifles. They have a great reputation and are known for innovative design in the components they produce.

John and Jeff Overstreet launched CMMG around two decades ago, primarily to sell AR parts and accessories. After several years, they started to make their rifles, and that’s how the siblings officially formed CMMG, Inc. They’ve come a long way since then. From a small eCommerce site, the brothers found a standing within the gun industry as a rising manufacturer for AR-15s, including rifles and firearm accessories.

Overview of the CMMG M4 Barrel

The CMMG M4 barrel is a Mil-spec certified chrome-moly vanadium steel barrel that features a 5.56 x 45 NATO hard chrome-lined chamber and bore.

Like most 6.5 Grendel barrels, the CMMG M4 barrel has a 1:7 twist so the bullet rotates faster. The barrel is individually magnetic-particle tested and engraved CMMG MPC.  It also has an M4 contour for attaching 40mm M203 and 37mm less-lethal launchers. 




Key Features to Consider

Barrel Twist Rate

When choosing a barrel, twist rate will be one of your primary decisions and will be based in part on caliber. Twist rate is the distance, in inches, it takes the bullet to rotate a full 360-degrees in the barrel. A 1 in 7 (or 1:7) twist means that the bullet will make one full revolution for every 7 inches it moves through the barrel. By comparison, with a slower 1 in 12 twist (or 1:12), the bullet will complete one revolution in a foot or 12 inches of the barrel.

This rotation stabilizes the bullet in the air, as long as the twist rate is appropriate for the caliber of bullet. Accuracy will greatly suffer if you get this one wrong. But it’s fairly straightforward to get it right. Longer, heavier bullets benefit from faster twist rates, like 1:7; while lighter bullets do well with a slower rate of twist. A 1:9 twist is generally a good compromise for most bullet weights so you may find that to be pretty standard.

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Barrel Profile

A barrel’s profile refers to the barrel’s diameter or thickness. This decision will determine how long your barrel maintains accuracy when shooting long strings of fire.

Thinner barrels (i.e. pencil or A1) are lighter to carry but accuracy will be affected faster as the barrel heats up. Heavy barrels (i.e. “H Bars”) are less affected by heat but add weight to the rifle. A medium weight barrel offers a compromise and  is the most common type manufactured.

Construction - CMMG Barrels

The materials used to construct a barrel may also have a direct impact on its performance. Cold hammer forging, for instance, is known to enhance the strength of a barrel, provide a streamlined finish, and create good grain structure. [1] Stainless steels are useful for precision shooting, but it may not be an outstanding idea if you’re after rapid firepower.

CMMG Endeavor Rifle on Tripod

In this CMMG barrel review, we focus on the M4, which is chrome-lined. Chrome lining increases a barrel’s resistance to heat and corrosion and makes them very easy to clean. However, some shooters think chrome lined barrels cause an accuracy drop. We don’t see this with the CMMG barrels.


All CMMG products have a Lifetime Quality Guarantee against material defects and workmanship. The company will either replace or repair any defect at no charge to the customer. You’ll have to present a copy of your invoice or other proof of purchase if you wish to submit service work. However, if the returned products are found to be without glitches or flaws, you’ll have to pay a restocking fee.

Is a CMMG Barrel Worth Buying?

Based on time with CMMG barrels we think CMMG offers excellent accuracy and durability for the money.

Looking for reliable handguns? Check out this Glock 43 and Kahr CM9 comparison here

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