As a gun hobbyist myself, I’ve heard how CMMG made quite a reputation in the gun community. Specializing in accessories like conversion kits, handguards, muzzle devices, and barrels for pistols and rifles, the company continues to thrive and take chances whenever they can. In this CMMG barrel review, we’ll see if they can provide ideal replacements or if there’s something better.
A 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. It has a 1:7 barrel twist rate and M4 feed ramps and barrel extension. 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. The CMMG barrel is commonly used for building a custom AR-15 upper.
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 the CMMG, Inc. They’ve come a long way since then. From being small-town website owners, the brothers found a standing within the gun industry as a rising manufacturer for AR-15s, including rifles and firearm accessories.
Key Features to Consider
CMMG Barrel Twist Rate
When looking for barrels, the twist rate is one thing that you should be very particular about. If you look inside your barrel, some grooves are known as the barrel’s rifling. These are measured by way of twist rates.
A twist rate is defined as the distance needed to spin the bullet through a full 360-degree rotation. For your AR-15, choose a CMMG barrel twist rate that ranges from 1:10 to 1:7. Like most 6.5 Grendel barrels, the CMMG M4 barrel has a 1:7 twist that causes the bullet to rotate faster.
When you talk about a barrel’s profile, you refer to both the barrel’s shape and weight. The profile is categorized into a lightweight, medium weight, or heavyweight profiles. Lightweight barrels or pencil barrels are lighter to carry around but won’t be as durable as the heavyweight profile.
Medium barrels offer a stable balance between durability and weight. There’s also what we call the Hanson profile, which features a lightweight profile and shoulder-less design. In choosing a profile, consider the firing conditions and the firing rate you’ll be using.
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.  Stainless steels are useful for precision shooting, but it may not be an outstanding idea if you’re after rapid firepower.
In this CMMG barrel review, we chose the M4, which is chrome-lined. Chrome lining is usually done in AR-15s and is considered the standard material for military rifles. A chrome lining increases a barrel’s resistance to heat and corrosion. However, it could cause an accuracy drop due to unevenness.
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.
We’ve heard good things about CMMG barrels, but we can’t say we haven’t caught some controversial issues about them, either. As per customer feedback, some claim that the company does not use the MIL-B CMV spec for their barrel construction. However, CMMG alleges that they do use this steel and presumably advertises that they do.
Is a CMMG Barrel Worth Buying?
Based on our CMMG barrel review and after spending a whole day out on the range, we think a CMMG barrel is a good enough product. We did have high hopes, though, so we weren’t keen on both the profile and the price.
For affordable yet quality barrels, Faxon Firearms is on top of our list. Aside from their impressive online reputation, we like how they also manufacture their barrels in-house. Faxon Firearms barrels are carefully constructed to withstand corrosion or any other performance issues.
Looking for reliable handguns? Check out this Glock 43 and Kahr CM9 comparison here.