The AR-15
is a modular weapon, and as a modular weapon, the design is endlessly customizable. You can buy or build almost any size and caliber of AR-15. One big decision you'll have to make is the barrel, and as far as barrels go, we have a lot to talk about.

Profile

Profile is the first thing we are going to talk about. Most discussions around profile revolve around the 5.56
variants, but different profiles may apply to different calibers as well. Profile is a way to describe how thick the barrel. Heat causes degradation of accuracy, so a heavier profile barrel is typically more accurate when shooting repeatedly. However, a heavy barrel is also heavy, and we like our rifles light, right? Like all things, you have to decide on what you want to do with the rifle before you choose the barrel profile. Are you going to be running long-range competition shoots? Then maybe a heavy barrel is for you. Are you looking to build a light home defense or duty carbine? The go-to with a lighter profile. Pencil - The lightest and thinnest. Perfect for reducing weight, but not optimal for rapid-fire mag dumps in the hundreds of rounds.

AR-15 .223 Wylde Lightweight Barrel

A2 - similar to the pencil, but heavier beyond the gas block for greater durability. M4 Profile - A thin profile until you reach the gas port. After that, the barrel gets heavier and thicker. On top of that, you have a 'cut' designed to accommodate an M203 grenade launcher. The heavier barrel forward of the gas port helps stabilize the weapon and reduce muzzle rise.

Anderson .300 Blackout AR-15 M4 Profile Barrel

Government Cut - Same as the M4, but lacks the grenade launcher cut.

AR-15 .223 Wydle Government Barrel

Heavy - Heavy barrels are thick from one end to the other and are, of course, literally heavy. They offer repeatable accuracy even after firing lots of rounds.

AR-15 .223 Wylde Heavy Barrel

Next you will need to determine how long or short of a barrel you will need:

Barrel Length

The barrel length of an AR-15 rifle can vary wildly between different designs, intents, and even calibers. Some calibers are designed for certain barrel lengths, and others simply work better with a shorter barrel. Barrels can be as long as 24 inches, and as short as 5.5 inches. When choosing a barrel length, you typically have to look at the caliber you want to shoot, as well as the goal of the rifle or pistol. Rounds like the 5.56 are designed to work in a 20-inch barrel, but because of the round and rifle's popularity, they can come in any length on the barrel scale. Rounds like the 9mm are popular in AR-15 barrel lengths get even shorter with 4.5-inch options that still deliver excellent performance. These are the most common barrel lengths you'll run into with AR-15s.

Rifle Length - 24, 20, and 18

Rifle length barrels give you the longest barrel to increase the velocity of the round. Increased velocity means the round goes further and hits harder. These barrels also give you a softer shooting gun that has less recoil and muzzle rise.

AR-15 24" .224 Valkyrie Barrel

Carbine Length 14.5 to 16 inches

This trimmer and shorter barrels give you a lighter and handier rifle. These rifles are easier to use inside and outside of buildings and vehicles, while still retaining enough velocity to reach out to considerable ranges.

AR-15 16" .223 Wydle Government Barrel

Shorty Lengths 10.3 to 12.3 inches

These short lengths are perfect for super-compact rifles designed for clearing rooms and running in and out of vehicles. These shorter barrels cut velocity quite a bit, and give you some significant concussion and noise. With pistol calibers, you can squeeze out more velocity.

AR-15 10.5" 7.62x39 Barrel

Super Shorties 5.5 to 7.5

These super-short barrels make your rifle as small and compact as it can be. The downside is another tremendous loss of velocity from rifle rounds, and a tremendous increase in noise. At the pistol level, these can be an excellent short barrel for sub-gun sized AR-15s.

AR-15 7.5" 9mm Barrel

Twist Rate and Rifling

Rifling is the arrangement of spiral grooves in the bore of a barrel. This spiral rifling spins the bullet and stabilizes it. This is an absolute requirement to make rifles accurate, and rifling comes in different twist rates. Twist rates affect how the bullet is stabilized, and different weight projectiles require different twist rates for the utmost accuracy and for stabilization. Some twist rates are designed for heavy barrels and others for lighter bullets. In the 5.56 realm, twist rates like 1:7
, 1:8
, and 1:9
are common. What do these numbers mean? Well, it's simple. When you see 1:7
, this means the projectile makes one full turn inside the barrel every 7 inches. The smaller the second number, the faster the barrels rifle twist is. The general rule of thumb is that heavy bullets like a faster twist rate. Because the AR-15 comes in so many calibers, we'd have to write a book to give you the best answer for every caliber, and we simply don't have the time for that. Do a bit of research your caliber and the ammo you are most typically going to use and then choose the twist rate that works for you.

Over a Barrel

The popularity of the AR-15 is what gives us so many options. Options are good, but so many different little things can confuse new shooters. Hopefully, we've taken out some of the mystery of the AR-15 barrel, and you can choose or build the rifle of your dreams. Shop All Lightweight Barrels
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