There’s nothing better than shooting a sleek, powerful AR pistol… except shooting one that you build with all your favorite custom parts. So, why doesn’t everybody jump on board the pistol-building express? One word: Feds. But, with a little finesse and a lot of knowledge about your local gun laws, you too can confidently build a classy AR pistol.
Note: This article is for educational purposes only; it is not meant to be construed as legal advice. You are ultimately responsible for your own actions and we advise you to seek guidance from a legal professional in your area before attempting any AR pistol build.
Why choose an AR pistol?
The first question you may be asking is, “Why choose an AR pistol over a standard rifle?” My initial response would be, “Why not both?” But, in all seriousness, an AR pistol provides you with more maneuverability, especially in tight spaces, and depending on your configuration, can give you most of what a standard AR-15 carbine does. Additionally, if you plan to run a suppressor, the shorter barrel will give you a similar overall length to a rifle.
Although an AR pistol can be more lightweight and maneuverable, there are some drawbacks. Because you have a shorter barrel, you’re going to get less velocity out of your caliber of choice. This is more of an issue for some, rather than others. For instance, the lightweight bullets in 5.56 NATO derive most of their power from velocity, however, the .300 AAC Blackout was purpose-designed for shorter barrels. Do some research on your intended caliber and see what barrel length works best for you.
Additionally, an AR pistol will have more muzzle blast, concussion, and felt recoil than a comparable rifle. This is most noticeable indoors and is a factor you should consider depending on where you shoot and your intended purpose for the firearm.
AR Pistol Laws and Definitions
The first thing to note about any custom build to make sure you stay safely within the law of your local and state gun regulations. Call your local FFL. They should be able to get you that information pretty easily. As a general rule though, a short-barreled rifle classification is what you want to avoid. How are those classified? A rifle with less than a 16-inch barrel or an overall length of less than 26 inches will get you that unwanted $200 NFA (National Firearms Act) tax. Additionally, per ATF guidelines, AR pistols equipped with braces may not have a length of pull longer than 13.5 inches — in other words, at full extension, the distance between the trigger and the rear edge of the brace cannot exceed 13.5 inches.
Another important note is how the BATFE (Bureau of Alcohol, Tobacco, Firearms, and Explosives) defines a rifle vs. pistol. In short, a rifle is anything with a stock that you fire from your shoulder. The ATF defines a pistol as “…a weapon originally designed, made, and intended to fire a projectile (bullet) from one or more barrels when held in one hand, and having: a chamber(s) as an integral part(s) of, or permanently aligned with, the bore(s); and a short stock designed to be gripped by one hand at an angle to and extending below the line of the bore(s).” But, hang on. I’ve seen tons of AR pistols that look almost identical to an AR rifle. What gives? And how are they avoiding the NFA tax? The answer? Pistol braces.
Bracing for Impact
In an open letter to the BATFE, the question was posed whether a brace, which traditionally has hand-holds or arm straps to help the shooter stabilize their shot while firing with one hand (fitting our pistol definition), would still classify the firearm as a pistol even if the shooter “happened” to “accidentally” place the end of the brace on his shoulder. Initially, their answer stated that this type of shouldering would qualify the weapon as an SBR under the NFA. In 2017, however, that statement was amended to read as follows:
“With respect to stabilizing braces, ATF has concluded that attaching the brace to a handgun as a forearm brace does not ‘make’ a short-barreled firearm because… it is not intended to be and cannot comfortably be fired from the shoulder… Therefore, an NFA firearm has not necessarily been made when the device is not re-configured for use as a shoulder stock — even if the attached firearm happens to be fired from the shoulder.”
So, if you’re looking to add that extra stabilization to your build with a brace, the BATFE has given the green light.
Keeping Your Weapon Legal
The main thing to ensuring your build is legal is to keep it under the “pistol” definition. Here’s how:
- Use a stripped lower receiver that has never been barreled as a rifle action. Or a receiver that started out as a pistol in the first place. If the receiver started out as a rifle and was classified as a rifle, you’re in trouble. Interestingly enough, if the receiver started as a pistol, you can strip it, convert it to a rifle and then back to a pistol without a problem.
- Use an angled foregrip such as the Magpul AFG that is less than 26 inches from the unadorned tip of the barrel to the end of the buffer tube. A vertical foregrip is not allowed on a pistol.
- Stay under the 16-inch barrel length and 26-inch overall length.
Really, if you follow these guidelines along with your local laws, building a legal AR pistol is a piece of cake. Now, since I know you’re wondering, here are some of my favorite components when building my ARs.
My Go-To Components
If you’re anything like me, you’ve got an ideal product for every square inch of your custom gun. But, just in case you’re in the market for some killer ideas, here are some of my top choices for custom builds:
- Black Rain Ordnance AR15 Complete Lower Parts Kit Enhanced Version Magpul MOE Pistol Grip/BRO Drop In Trigger
- Spikes Tactical Rare Breed Crusader Stripped AR-15 Lower Receiver
- SB Tactical SBA3 Adjustable Brace
- Aimpoint PRO Patrol Rifle Red Dot Sight
- Yankee Hill Machine Ar-15 Muzzle Brake
- Midwest Industries AR-15 Combat Rail T-Series Free Float Handguard
- CMMG AR-15 Complete Lower Parts Kit
Whatever parts you choose to build your perfect AR pistol, have fun with it and be sure to keep it legal with the above tips.
Have you legally built an AR pistol? How did it turn out? What’s your favorite barrel length, caliber, and setup? Let us know in the comment section!
Editor’s note: This post was originally published in September of 2020. It has been revamped and updated for accuracy and clarity.