AR-15 Barrel Length Explained

I shamelessly poached this from Classic Firearms, I have bought pistols from them before as well as parts and found them as a good source.  I haven't bought anything recently during the kung-flu so I don't know how they are doing.  I have been exceedingly frugal with my firearm dollars because of the unknown nature of what to expect.

This entry was posted on May 1, 2020 by Travis Pike.

Barrel length and the AR-15 

The AR-15 is a fascinating rifle. Not just its long history of service, or the fact that it’s America’s favorite rifle, but also from an engineering perspective. The rifle is incredibly modular, and you can pick and choose parts like no other weapon out there. One major change you can make is with the barrel length. There are a wide variety of barrel lengths you can use for your gun, so we’ve broken them down here. 

The Rifles 

24 Inches 
A 24-inch barrel is an odd one, and when it comes to a 5.56 AR, there are not many advantages to the four extra inches of barrel. However, in calibers like 6.5 Grendel, the extra barrel length can get you extra velocity, which adds extra range and hitting power. 

AR-15 .224 Valkyrie 24" Barrel

20 Inches
Twenty inches is what the original 223 Remington round was built for. 20-inch barrels allow you to maximize the velocity of a 5.56 or 223 Remington round. The extra barrel length not only provides extra velocity and range, but offers you a softer shooting, smoother handling rifle. 

The Weird One

18 inches
Eight inches is an odd barrel length, but it’s a cool idea rooted in Special Operations. The 18-inch barrel allows you to use a rifle-length gas system, which gives you the same recoil and muzzle rise impulse as a 20-inch barrel. It’s also two inches shorter, giving you a more handy rifle. 18-inch barrels are popular in the competition world due to their smooth shooting. 

AR-15 20" Barrel 6.5 Creedmoor

The Civilian Carbine Standard 

16 Inches 
16-inch barrels are the shortest a civilian can legally go as a title 1 firearm. Any shorter necessitates a pistol or short-barreled rifle. Sixteen inches gives you a light and handy rifle that makes good use of the 5.56 cartridge. It’s the most popular AR-15 barrel length. 

AR-15 7.62x39 16" Barrel

The Military Carbine Standard 

14.5 inches
14.5-inch barrels are the standard for the military’s M4 program. They are popular with civilians as well, but they have to be pistols SBRs, or a third option is choosing a 1.5-inch long muzzle device and pinning and welding it to create a 16-inch barrel. Like 16-inch barrels, the 14.5 is light and handy, and still retains decent velocity and range capability.

AR -15 .223 Wylde 14.5" Barrel

The Shorties 

12.5, 11.5, and 10.3 inches
These three lengths are super short and commonly found on rifles purpose-built for clearing rooms. All of these lengths require a pistol build or SBR. These three lengths all have reduced velocity, and therefore range, but are so light and handy they are perfect for inside of 300 yards. They can hit targets beyond that range, but they aren’t optimal for those distances. 

AR -15 .450 Bushmaster 10.5" Barrel

The Super Shorties 

7.5 inches and Below 
The super shorties are a little silly when your AR-15 is a 5.56. Rounds like the 300 Blackout and 9x19 can be effective from these super short barrels. These short barrel lengths make the guns even handier inside structures, but also easy to conceal in bags. These super short barrels can be a lot of fun, and when paired with a suppressor, you still get a light and short rifle. 

AR-15 9mm 7.5" Barrel

Suit Up 

Barrel length can completely change how a weapon handles, how it recoils, and even its legal status. Different calibers work with different barrels in different ways, so when you choose a barrel, you need to observe your purpose, your caliber, and your overall intent. Then you need to come to Classic Firearms and find the barrel or rifle you need.