The AR-15 platform is traditionally chambered in the .223 Remington and/or 5.56mm NATO cartridge. As a result of its modularity, several companies have designed, developed, and manufactured upper receiver assemblies and complete rifles chambered in alternative cartridges. One of these is the 7.62x39mm Soviet.
If you’re contemplating building an AR-15 chambered in this Soviet powerhouse, one of the first parts you’ll need is a barrel. The length of the barrel, its contour, the type of steel it’s made from, and its coating all affect its accuracy potential, heat dissipation, corrosion resistance, and more. Consider all of these factors carefully when making your selection.
A heavier barrel, all else being equal, will absorb heat more efficiently and experience less expansion — it also tends to be more rigid. A fluted barrel, all else being equal, is lighter and will cool faster.
Best 7.62×39 AR-15 Barrels
1. Faxon Firearms 7.62×39 Russian Gunner Rifle Barrel
Faxon Firearms has built a reputation as a high-quality manufacturer of AR-15 parts; however, the firm doesn’t only produce .223/5.56mm AR-15 barrels — it also strives to fulfill the demand for other calibers. The Gunner Rifle Barrel is available in two lengths: 10.5” and 16”. The 10.5” barrel is for your short-barreled rifle or pistol build, and the 16” barrel is for your carbine or rifle build.
Manufactured using 4150 CMV (chrome-molybdenum-vanadium) alloy steel, the Gunner Rifle Barrel features an M4 extension, 1:8” rifling twist rate, and nitride finish for protection against rust.
A mid-length gas system is more appropriate for this barrel length.
2. Diamondback Firearms 7.62x39mm AR-15 Carbine Barrel Nitride — 10”
Whether you’re planning to build a short-barreled rifle or a pistol in 7.62x39mm, Diamondback Firearms’ 10” carbine barrel is an excellent place to start. Machined from 4150 CMV steel, Diamondback Firearms button rifles the barrel, imparting six rifling grooves with a twist rate of 1:9.5”. As part of your SBR or pistol build, the company recommends using a carbine-length gas system to ensure optimal functioning.
The muzzle of the barrel is important too, and features an 11° target crown and ⅝”x24 thread.
For increased corrosion and wear resistance, the company applies a salt-bath nitride finish, ensuring that the barrel is protected against rust.
3. AR-STONER Barrel AR-15 7.62x39mm Heavy Contour 1 in 10” Twist Chrome Moly Phosphate
The AR-Stoner 7.62x39mm barrel is close to mil-spec but chambered in the former Soviet cartridge. Machined from 4140 chrome-molybdenum, this barrel has a heavy contour, which increases its ability to absorb heat from rapid-fire range sessions. 4140 is a strong steel alloy used extensively in the firearms, gas, and oil industries.
The manufacturer has installed the barrel extension and locator pin, which simplifies the assembly process. To protect against corrosion, this barrel has a phosphate or parkerized, matte-black finish. As with other offerings, the AR-Stoner has a ⅝”-24 threaded muzzle and a 1-in-10” twist.
4. Yankee Hill 7.62x39mm 1:9.5 Melonite, Threaded, Fluted Barrel — 16”
Last but not least is the Yankee Hill contribution to the list of 7.62x39mm barrels for the AR-15 platform. While the Yankee Hill Machine, or YHM, barrel has the same rifling twist rate as the Diamondback Firearms offering, one of the key differences is the fluting.
Flutes, or milled longitudinal grooves, reduce weight by removing material. Fluting also serves to increase the rate of heat dissipation by increasing the surface area of the barrel.
To protect the barrel against corrosion and increase its surface hardness, Yankee Hill applies a Melonite finish. Melonite, a type of ferritic nitrocarburizing. In addition to protecting the surface of the barrel against rust, it also avoids the potential decrease in accuracy associated with chrome plating. This potential decrease can result from an uneven distribution of chrome on the bore.
The Cold War
The Soviet Union developed the 7.62x39mm cartridge in 1943. A bottlenecked, intermediate-powered cartridge, the 7.62x39mm, would see use in famous Soviet weapons such as the SKS, RPD, AK-47, and RPK. China would follow suit with the Type 56.
During the Cold War, NATO standardized the 7.62x51mm NATO. The Belgian FN FAL — the “right arm of the free world” — American M14, and West German HK G3 would exemplify weapons chambered in this cartridge: long, heavy, selective-fire battle rifles fed from 20-round box magazines. The weight of the ammunition limited the number of rounds an infantryman could carry, and the weight and bulk of the rifle limited his maneuverability.
A lighter caliber was required. A .22-caliber cartridge loaded with a lightweight, high-velocity projectile would enable a soldier to carry a correspondingly lighter weapon and more ammunition for the same weight, increasing his combat effectiveness. The result was the .223 Remington, which would become the 5.56mm M193 and, later, the NATO-standardized SS109 (American M855). The M193 cartridge used a 55-grain bullet, which was replaced by a 62-grain bullet in the SS109.
While the U.S. and its allies adopted 5.56mm carbines, infantry rifles, and light machine guns, the USSR kept a wide variety of weapons chambered in 7.62x39mm Soviet.
7.62x39mm vs. 5.56mm NATO
The 7.62x39mm is one of the most common intermediate rifle cartridges globally, seeing extensive use in Kalashnikov-pattern assault rifles and light machine guns. Using a comparatively heavy bullet for an infantry weapon — typically between 123 and 150 grains — the 7.62mm round exhibits superior penetration regarding building materials and other chance barriers than the commercial .223 Remington or military 5.56mm NATO.
Furthermore, surplus ammunition and AK-47-pattern magazines are widely available for relatively low prices.
As the cartridge casing has a more acute taper, it extracts reliably under a variety of conditions. This taper contributes to the reliability of firearms chambered in this cartridge.
The less energetic 5.56mm cartridge tends to inflict more traumatic wounds due to its propensity to yaw, tumble, and fragment in soft tissue.
As its muzzle velocity is considerably higher, it has a flatter trajectory and is, thus, more suitable for precision shooting. However, the 5.56mm round — at least in its full metal jacket variants — is also dependent on entry velocity for these terminal wounding effects.
Why a 7.62mm AR-15?
Not everyone is a fan of the AK-47 pattern. Although the AK-47 is reliable, rugged, and simple to operate, many shooters find it decidedly less ergonomic than the ArmaLite pattern. If you want the AK’s caliber in a more user-friendly package, you can buy or build an AR-15 in 7.62x39mm.
The AR-15 also has the advantage of being a closed system. Unlike the AK-47, dirt, sand, and mud are less likely to enter the AR-15’s action. This system reduces the likelihood of the weapon experiencing a malfunction.
Home Defense and Hunting
If you need a rifle, carbine, or rifle-caliber pistol for self-defense inside the home, a .223-caliber or 5.56mm weapon is the superior choice. The lighter 5.56mm bullet is more likely to break apart on impact with interior walls, limiting penetration that may injure or kill bystanders.
If, however, you need a weapon that can penetrate car doors, concrete or brick walls, or other barriers to reach your assailant, the 7.62mm excels in this regard.
As the 7.62mm cartridge uses heavier bullets, it is potentially more effective for hunting deer-sized game animals, achieving deeper penetration; however, it also produces more recoil. The 5.56mm cartridge, even in especially lightweight weapons, is manageable.
.300 Blackout
While the .300 AAC Blackout can outperform the 7.62x39mm at medium range, it is also generally less available and more expensive. As the .300 Blackout is also based on the .223 Remington cartridge, it’s more suitable for use in an AR-15-platform action.
Furthermore, the taper of the 7.62mm Soviet round causes a pronounced taper in the magazine. The .300 Blackout, having a relatively straight case, avoids this. The result is that you can use standard USGI or STANAG 30-round magazines.
It’s worth noting that there is a risk of inadvertently loading .300 Blackout cartridges into a 5.56mm magazine and rifle. The 7.62x39mm cartridge will not chamber in a 5.56mm barrel. The .300 Blackout, however, will enter a 5.56mm chamber, headspacing on the bullet. This chambering can cause a catastrophic failure if fired.
Other Considerations for 7.62x39mm AR-15 Barrels
The barrel is only one, albeit important, component of your rifle build. When you’re assembling an AR-15-pattern weapon, don’t neglect suitable bolt carrier groups, receivers, and other parts necessary to the reliable function of your firearm. The same is true regarding magazines. A poor-quality magazine can cause failures to feed and other stoppages.
While the 7.62x39mm cartridge is not capable of the same degree of accuracy as the 5.56mm, it’s still worth investing in a high-quality barrel to ensure that you gain the most advantage from your build and the cartridge.
Final Thoughts
7.62x39mm ammunition is relatively inexpensive, available, and sufficiently powerful for both defensive and hunting applications. However, rather than purchase an AK-47-pattern rifle, many shooters prefer to use the hard-hitting Soviet caliber in an AR-15-platform weapon, preferring its ergonomics and modularity. Every rifle build should start with the barrel — the heart of the gun — and there are a few to choose from.
