The AR-15 platform is a highly versatile and modular design. In building an AR-15, you can choose from dozens of different barrel options, each with its own strengths and weaknesses, to suit a variety of applications, from self-defense to competitive target shooting.
Best AR-15 Barrels
Several companies manufacture AR-15 barrels, offering barrels of different lengths, materials, outside profiles, chambers, and more. In this market, you can find almost any type of barrel that you could need.
1. Faxon Firearms Gunner 5.56mm Pencil Barrel
Faxon Firearms is a well-known manufacturer of AR-15 barrels, parts, and accessories. The Gunner profile represents a hybrid contour. The rear part of the barrel, from the barrel extension to the gas block journal, retains the standard government profile and taper. This increased material thickness reduces the phenomenon of barrel whip and absorbs heat.
The front part of the barrel, extending from the gas block to the muzzle, is pencil-thin. Being so narrow saves weight — a front-heavy rifle can cause increased fatigue, especially if you have to carry your rifle for a protracted period.
Faxon Firearms offers its Gunner-profile barrels in either 4150 CMV and 416R stainless steel.
This particular barrel has a 5.56mm NATO chamber, a 1:8” rifling twist rate, and a button-rifled bore.
2. Faxon Firearms .223 Wylde Heavy Fluted Rifle Barrel
If you’re not interested in a 5.56mm chamber, Faxon Firearms also supplies several barrels featuring the hybrid .223 Wylde chamber. In a .223 Wylde chamber, you can fire both commercial .223 Remington and military 5.56mm ammunition without a decrease in accuracy or safety.
One of the stand-0ut features of this barrel is that it has flutes, which are longitudinal grooves milled into the outside diameter of the barrel to reduce weight. The fluting also increases the surface area of the barrel, which helps to cool it.
3. Ballistic Advantage Performance Series 5.56 AR Rifle
Ballistic Advantage manufactures rifle barrels for various applications, but one of the most interesting innovations this company has devised is the Hanson barrel. The Hanson barrel features a taper from the gas block journal to the muzzle, eliminating the shoulder common to government-profile barrels. This change reduces weight and eliminates asymmetry that may adversely affect accuracy.
In addition to the unique profile, Ballistic Advantage applies a nickel-boron coating to the barrel extension and a QPQ (quench, polish, quench) nitrocarburizing treatment to the barrel. These increase corrosion resistance, protecting the barrel from rust and ensuring that it’s ready for any environment.
Ballistic Advantage offers its range of barrels in both 5.56mm and .223 Wylde chamber designs and manufactures every barrel using mil-spec 4150 CMV. The company also offers 11.3” barrels for pistols and short-barreled rifle builds as well as longer barrels for precision shooting.
4. Rainier Arms MOD2 UltraMatch
Rainier Arms’ MOD2 UltraMatch features the company’s proprietary barrel contour and stainless-steel construction.
The company chose to apply a gold-colored TiN (titanium nitride) surface treatment to the barrel extension, which is both attractive, although hidden when assembled, and increases lubricity. While it’s difficult to say whether increased lubricity confers a noticeable improvement in bolt seating or locking, a smoother action is always preferable.
The stainless-steel construction is both cosmetically appealing and inherently corrosion-resistant.
5. PROOF Research PR15 Carbon Fiber 223 Wylde
PROOF Research offers a special-purpose barrel on the more expensive side, featuring the hybrid .223 Wylde chamber. A 416R stainless-steel barrel blank, PROOF Research turns down the outside profile and encircles the barrel in carbon fiber.
The carbon fiber, which is both strong and stiff, allows for a significant weight reduction — up to 64% compared with all-steel barrels of the same length and profile. In addition to reducing weight, the composite design dissipates heat more efficiently than traditional steel barrels.
The company also advertises its barrels as further reducing harmonic vibration, which may improve accuracy.
However, these reductions are costly — almost twice as expensive as other, more traditional designs. You’ll have to determine for yourself whether these advantages are worth the additional expense.
Put simply, a barrel is a metal tube through which a projectile is fired. The front of the barrel, from which the bullet exits, is the muzzle. In AR-15 barrels, the muzzle is typically threaded to accept a muzzle device, such as a flash suppressor or recoil compensator.
The rearmost part of the barrel is called the breech. At the breech end of the barrel is the chamber, a compartment cut to accept a specific cartridge.
The bore is the inside diameter of the barrel, consisting of rifling. Rifling is a series of spiral grooves cut or formed into the bore that cause the bullet to rotate in flight. This rotation stabilizes the bullet gyroscopically, allowing it to travel farther and more accurately.
Threaded muzzles allow you to attach several muzzle devices, each serving a different purpose. The standard AR-15 muzzle device is a flash suppressor or flash hider. The purpose of the flash suppressor is to exhaust and dissipate propellant gases to reduce the brightness of the muzzle flash. Although it’s commonly thought that the flash suppressor is designed to reduce a soldier’s visibility to enemy personnel, the essential function of this device is to avoid blinding a rifleman in low light.
The shorter the barrel, the more important this becomes.
Other than reducing the muzzle flash, you also have muzzle brakes, recoil compensators, and sound suppressors:
● Muzzle brakes and recoil compensators
Although often used interchangeably, a muzzle brake is primarily designed to reduce rearward recoil, while a compensator is designed to reduce muzzle climb. These functions can overlap, but the emphasis is important.
Muzzle brakes are often a requirement of heavy-caliber or magnum rifles to reduce user discomfort and fatigue. Compensators are typically found on fast-shooting weapons — e.g., competition weapons, submachine guns — where controlling the position of the muzzle in relation to the target is critical.
● Sound suppressors
Sound suppressors, also called silencers, reduce the report at the muzzle by capturing high-pressure, hot powder gases, slowing and cooling them. While the sound suppressor is often associated, culturally, with criminals, spies, and assassins, the device began as a civilian sporting device. As the sound suppressor reduces the sound of the gunshot considerably, it can be considered a safety device.
Cold Hammer Forging
In the cold hammer-forging process, the manufacturer inserts a mandril into a barrel blank. The mandrill has the outside profile of the firing chamber and the lands and grooves of the rifling pattern. The mandril and barrel blank are placed into a forge in which hammers repeatedly strike the outside diameter. The compressive force imparts the rifling and chamber pattern of the mandril on the inside diameter of the barrel. The blank, during the forging processes, is lengthened.
Cold hammer forging eliminates some of the chamber and bore roughness that traditional machining operations sometimes leave behind. It also compresses the grain structure of the steel, increasing strength.
AR-15 barrels, being steel, are susceptible to varying degrees of corrosion. Chrome plating is a common way of protecting the bore against rust — this is in accordance with military specifications. However, as the chrome plating may not be evenly deposited, it can interfere with the precision of the barrel.
Ferritic nitrocarburizing and salt-bath nitriding are surface finishes that penetrate the surface of the steel. In addition to blackening the barrel, these processes increase surface hardness, wear resistance, and corrosion resistance, without affecting tolerances — there is no build-up.
AR-15 Barrel Lengths
Firearms conforming to the AR-15 pattern are available in a variety of different barrel lengths. These can be grouped into three categories along with the compatible direct-impingement gas system length.
In barrels less than 10”, which are common to AR-15-pattern pistols, the gas system length is 4”.
The first type of gas system above the pistol variety is carbine-length, which you may use with a 10–18” barrel. This gas system is 7 inches.
For carbines with a barrel between 14 and 20”, which covers most AR-15-pattern weapons, many gun owners regard the mid-length gas system as optimal. This substitutes a length of 9–9.5”, increasing the dwell length and lowering the pressure. Lower pressure equates to reduced bolt velocity.
If you’re assembling a rifle with a barrel of 20” or more, you should be using a rifle-length gas system in which the port is 12–12.5” from the receiver.
The barrel length affects several factors related to both the cycle of operation and the ballistics of the cartridge. As a rule, the longer the barrel, the higher the muzzle velocity, all else being equal. A longer barrel is not necessarily more accurate; however, a higher muzzle velocity does correlate with a flatter trajectory and less wind deflection.
The chamber is necessary for containing the explosion during cartridge ignition. There are, however, three types of .223/5.56 chambers:
● .223 Remington
● 5.56×45mm NATO
● .223 Wylde
While the .223 Remington and 5.56mm cartridges use the same diameter bullet and share the same external dimensions, they are not strictly interchangeable. It’s safe to fire .223 Remington ammunition in a 5.56mm NATO chamber, but the reverse is not advisable. This inequality is due to differences in throat length and chamber pressure. As a result, firing 5.56mm NATO ammunition in a .223 Remington chamber is considered unsafe.
Although it’s safe to fire .223 Remington in a 5.56mm chamber, you may experience a loss of accuracy.
A hybrid chamber, .223 Wylde allows you to safely fire both cartridges in the same chamber without a discernible loss in accuracy potential.
The AR-15 barrel that you choose for your build should reflect your needs. Barrel material and finish protect the outside profile and bore against corrosion, fluting, and tapering reduce weight, and the contour affects barrel whip and vibration. You should find the balance that maximizes your potential in the field or on the range.