How to Build an AR-15 & What You Need to Know

Disclaimer: This blog is for educational purposes only and not intended to provide legal advice. You are responsible for your own actions, and we advise you to seek guidance from a legal professional in your area before building a custom AR-15 pistol.

 

Should you be afraid to build your own AR pistol?

 

Lions, tigers, and custom-built AR pistols. Oh my!

 

As a law-abiding citizen, we understand that building your own AR pistol can feel like walking on eggshells. It’s one thing to learn how to safely make a firearm that will work great for your needs—and quite another when it comes to building it according to all the convoluted rules in place. 

 

Have no fear. We will walk you through the steps of what you need to get started.

 

What you need to know before building an AR-15 pistol

 

The fears behind building a custom AR-15 pistol are not primarily focused on preventing yourself from getting caught in the act of using an illegally configured firearm at the range—but more about protecting yourself in case you ever need to use it in a personal defense situation, where your firearm can be seized and used as evidence against you in court. 


For rest assurance (and to remain the law-abiding citizen we know you are), building a firearm legally is truly a “cover your ass” action that calls for getting it done right the first time. It’s not worth cutting corners that could cost you a whole lot of issues in unexpected circumstances. 

 

Before we get into the nitty gritty, let’s cover our bases.

 

The first thing you want to do is familiarize yourself with both your local and state gun regulations, or contact your local FFL dealer for guidance. They can help answer questions and provide suggestions as well.

 

Now let’s define what a pistol is on a federal level.

 

The Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) defines a pistol as “a weapon originally designed, made and intended to fire a projectile from one or more barrels when held in one hand and having: a chamber as an integral part of, or permanently aligned with, the bore; and a short stock designed to be gripped by one hand and at an angle to and extending below the line of the bore.”

 

While an AR-15 pistol has a similar makeup as an AR-15 rifle, there are a few differences that classify it a “pistol”: 

  • The barrel is typically shorter than 16 inches (and overall length is shorter than 26 inches).
  • You can’t put a vertical forend grip on it (angled grips are okay).
  • You can optionally have a pistol brace on your firearm.
  • It cannot have a stock.

 

Also, the NFA (National Firearms Act) doesn’t regulate pistol barrel length. So as long as it doesn’t have a stock, which would classify it as a rifle, you should be good to go without having to deal with the tax stamps, paperwork, and other rules from the NFA.



How to build an AR-15 pistol

how to build an ar-15 pistol

Now let’s get to the good stuff: building a custom AR-15 pistol. 

 

The benefit of building an AR-15 pistol is that you get exactly what you want–sometimes at a fraction of the cost. As long as you have the time on your hands, it can be a great alternative to buying one from a firearms dealer. 

 

First things first, you need to define your budget and what you want from your firearm.

 

Now it’s time to get a lower and upper receiver from your FFL. Ensure the 4473 form is marked “Other receiver, other firearm and receiver (not rifle).” You must know how the lower receiver part was purchased. If it was originally built as a rifle, it can’t be built into a pistol without getting a tax stamp and registering it with the ATF. But if you bought a stripped lower receiver and built it into a pistol from scratch (and it’s not designated as a rifle on the 4473 form), you’re gravy.

 

Here are some other items you’ll need:



  • Handguard
    • A handguard (also known as a forend or forearm) is a shroud that covers the barrel, preventing accidental burns and allowing a second surface for gripping the firearm. There are free-floating and drop-in handguards available based on your needs.



  • Bolt Carrier Group (BCG)
    • This is something you don’t want to go cheap on. It’s the part of the rifle or pistol that allows for safe semi-automatic action.


  • Barrel
    • You need to determine which caliber you want: .223/5.56mm, .300 Blackout, 9mm, .45 ACP, etc.
    • You will want to ensure the barrel’s gas port is in the desired location: carbine or rifle. Carbine-length gas systems are the de facto standard for most pistol builds these days.
    • An AR-15 pistol also usually has a barrel shorter than 16” (the minimum legal length for a rifle barrel).



  • Trigger
    • You can stick with a standard mil-spec trigger or consider an aftermarket trigger. The sky’s the limit when it comes to function and features of the myriad aftermarket triggers.





  • Pistol buffer
    • A pistol buffer is another piece designed to help make your AR semi automatic. Example of an AR-15 carbine buffer:



  • Buffer spring
  • Castle nut
    • A castle nut (or buffer tube nut) screws into the buffer tube and keeps the buffer tube/receiver extension and lower receiver end plate secured. Example of an AR-15 castle nut:
  • Endplate
    • An endplate is designed for an AR-15 with a carbine buffer tube, aligning the buffer tube with the lower receiver. Example of an AR-15 endplate:



 

Other add-ons we suggest:



  • Optics
    • We could write an entire book on optics and sights. Suffice it to say, do some independent research, ask others, and try out different options for yourself. First and foremost, you will need to determine whether open sights, a red-dot-type, a telescopic optic—or a combination thereof is what you’re looking for.



  • Flashlight for home defense
    • A flashlight mounted to your firearm will help you see where you’re going during the night and see your target, but a bright light can also stun your intruder, making it difficult for them to see you. 

Why You Should Choose an AR-15 Pistol for a Home Defense Firearm

Let’s cut to the chase: The AR-15 pistol is one of the best firearms for home defense. 

 

Why? They’re affordable, reliable, accurate, and found everywhere. It’s no wonder the AR-15 is informally known as America’s 21st Century musket. And for good reason. 

 

When an intruder sees the easily recognized AR in your hands, they know you mean business. 

 

Learn about the evolution of the AR and AR pistol

 

But first, let’s dive into the benefits of using an AR-15 pistol for home defense. Each benefit is like a ripple effect — they all go hand in hand to make this firearm perfect for defense purposes. 



Benefits of an AR-15 Pistol for Home Defense

 

shockwave blade stealth ar-15 pistol

Affordable

 

You can find an AR-15 pistol to fit every budget: from just a few hundred dollars to the “sky is the limit.” The typical .223 ammunition is easily found in stores (when there’s not a global pandemic unfolding daily or nightly riots) and one of the least expensive ammos, with prices averaging about 32 cents per round. 

 

 

Low Recoiling

 

A low recoil makes the AR-15 pistol easy to shoot and a good option for beginners — even younger members of the family.

 

 

Accuracy

 

Because of such low recoil, accuracy is improved for most shooters.

 

 

Lightweight

 

At a mere 6 pounds — with ammo! — the AR-15 pistol is light enough for shooters of all ages and experiences. Because it has such a lightweight body, you can easily customize and add accessories to your firearm without making it too heavy to handle safely and accurately — especially in a home defense scenario. 

 

 

Ergonomically Designed

 

Many features of the AR-15 pistol are designed with ergonomics in mind, making this firearm comfortable and safe to shoot: pistol grip, trigger reach, safety location, forward handguard, sights, etc.

 

 

Ammo Capacity

 

A typical AR-15 pistol magazine holds 30 rounds of ammo. 

 

Many experts recommend using the .223 cartridge because it’s typically easy to find in stores,  inexpensive, and provides lower recoil. Some recommend using a 55-grain soft-point load that minimizes bullet penetration, which can be beneficial to protect your family in other parts of the home (or surrounding neighbors) in case the bullet misses the intended target. However, as you may know, the AR-15 is available in a multitude of calibers.

 

 

Size

 

During a home invasion, you don’t want to be turning corners and allow the intruder to discover your location before you know theirs. The AR-15 pistol is a great option for home defense due to its relatively short length, allowing you to turn corners discreetly and avoid disclosing your location that can put your defense game at risk. 

 

 

Customizable

 

From function to ergonomics to aesthetics, there are simply too many types of firearm accessories for customizing your AR-15 pistol than we can possibly cover here: grips, forearms, slings, sights, lights, lasers, scopes, red dot sights, triggers, muzzle devices, and so on. 

 

For home defense purposes, however, we recommend keeping it simple. Focus on the following accessories:

  • Brace, grip and/or sling: for better and safer control of your firearm
  • Flashlight: for better visibility in low-light conditions and stunning any intruders with the bright illumination
  • Red dot sight: for accuracy



A note about pistol braces:

 

Whether you’re building a custom AR-15 pistol or bought an AR-15 pistol without a brace, adding a brace can improve control and accuracy.

 

An AR-15 pistol cannot have a stock but it can have a brace, such as the Shockwave Blade and Shockwave Blade 2M. 





Shockwave AR-15 Pistol Accessories

 

Shockwave Technologies offers products to enhance your home defense use (and enjoyment) of your AR-15 firearms. Check out these Shockwave products compatible with AR-15 pistols.

 

 

Blade®

 

Made from high-strength glass-reinforced polymer, the Blade® is manufactured to exacting tolerances and fits all pistols equipped with a standard AR-15 pistol buffer tube (up to 1.25? in diameter). Just slip it on and tighten the large set screw for a rock-solid installation.

 

Blade® fits all pistols equipped with a standard AR-15 pistol buffer tube (up to 1.25? in diameter) AR pattern, Glock, CZ Scorpion Evo 3, HK9X pattern, etc.

 

Features include:

 

  • Available in black, flat dark earth, OD green, and stealth gray
  • Quick and easy to install.
  • Provides additional support during firing.
  • Weighs a scant 5.0 ounces.
  • ATF approved for pistol use 

 

 

Blade® 2M

 

Made from high-strength glass-reinforced polymer, the adjustable Blade® 2M pistol stabilizer is manufactured to exacting tolerances and fits all pistols equipped with a Mil-spec buffer tube. Just slip it on and lock in place.  Adjusts with a simple finger lever.

 

Compatible with all pistols equipped with a Mil-spec buffer tube: 

 

  • AR-15 pattern
  • MPX
  • Glock
  • CZ Scorpion Evo 3
  • HK9X pattern
  • etc.

 

Features include:

 

  • Available in black, flat dark earth, OD green, and stealth gray
  • Quick and easy to install.
  • Provides additional support during firing.
  • Weighs a scant 4.0 ounces.
  • ATF approved for pistol use 

The Evolution of the AR and AR Pistol

What is an AR pistol?

AR pistol Shockwave

While an AR-15 pistol has a similar makeup as an AR-15 rifle, there are a few differences that classify it a “pistol.” To be exact, the barrel’s typically shorter than 16 inches, you can’t put a vertical forend grip on it, and you can optionally have a pistol brace on your firearm. 

 

 

Why would you want an AR pistol? 

 

Gun enthusiasts love shooting semi-automatic AR pistols for entertainment and target practice, but it can also be a great firearm for personal and home defense. However, many gun owners prefer a shotgun or a Mossberg 590 Shockwave for home defense.

 

Modern AR firearms are lightweight, durable, and easy to use. As long as it adheres to gun laws, AR owners can also customize their firearm how they see fit—from color choices to barrel lengths and accessories.

 

 

Evolution of the AR:

 

There’s a bit of history to tap into when it comes to understanding how the AR pistol became such a hit. Many consider AR firearms “American.” But looking into the subject deeper, its roots actually go back to the M1 Garand, which was a rifle designed by a French-Canadian. An unlikely candidate, eh? Back in the 1930s, John Garand was hired by the U.S. Springfield Armory to design guns. His .30-06 caliber, gas-operated, semi-automatic rifle was eventually adopted as the official U.S. infantry rifle used in action — including WWII and the Korean War. By 1938, the M1 Garand was mass produced and delivered to the Army for battle. After WWII, most M1 Garand rifles were put away into storage or loaned to allies fighting in battles, but as new wars sprouted (including when North Korea attacked South Korea in 1950), the M1 Garand started going back into production until 1957. 

 

But things started to shift in the 1950s when the AR-10 was born. Eugene Stoner, a former Marine and Army Ordnance technician, helped design that firearm out of aircraft-grade aluminum, allowing for a mere 7- to 9-pound weapon that would be beneficial for soldiers constantly carrying around their firearm for protection and battle. This new infantry rifle design also had a larger capacity magazine and select-fire capability. 

 

Despite popular belief, the “AR” stands for ArmaLite Rifle, not “assault rifle” or “automatic rifle.” ArmaLite is a firearms engineering company based out of California and where the AR-10 name derives. This firearm was built as a magazine-fed, gas-operated rifle firing a 7.62mm bullet. By 1960, a scaled-down version, firing the 5.56mm cartridge, started making its way through the military world. However, ArmaLite’s lack of successful firearm sales led them to sell the design to Colt’s Manufacturing Company, and the U.S. Military hired Colt to start pushing out loads of a full-auto version, designated the M16, to soldiers fighting in Vietnam. 

 

Not long after, Colt released a semi-automatic AR-15 version—the SP1—to the public for purchase, and sales have continued to boom. Today, there are millions of Americans who own AR-15s and there are over 150 manufacturers of AR parts. 

 

Because of the continued popularity of the AR firearm in households, many manufacturers, sellers, and even gun owners are influencing the evolution of the AR. 

 

Several years ago, the creator of the Shockwave Blade was inspired to create a smaller, lighter, more-affordable pistol brace. The Shockwave Blade® Pistol Stabilizer is veteran designed, engineered, marketed, and sold in the U.S. It’s made from high-strength glass-reinforced polymer, manufactured to exacting tolerances, and fits all pistols equipped with a standard AR-15 pistol buffer tube (up to 1.25? in diameter). Just slip it on and tighten the large set screw for a rock-solid installation. The Blade 2M, Shockwave’s newest Brace, is designed to fit any standard mil-spec carbine buffer tube and adjusts with a simple trigger lever.

 

Shockwave’s pistol blade stabilizer is also ATF approved for pistol use. Although it’s illegal (and a felony) to have a stock on an AR pistol function without ATF approval and a tax stamp, there are many foreign firearm sellers online trying to scam gun owners into buying illegally produced products and fakes. When you buy directly from Shockwave, you can ensure to receive American-made, ATF-approved products for your firearm.



 

What are the laws of owning an AR pistol?

 

Before we get into the nitty gritty of gun laws, you should refer to your official state and local gun laws for legal advice. You can also contact the ATF (Bureau of Alcohol, Tobacco, Firearms and Explosives) for more information about the AR pistol.

 

But for general info about this firearm, keep reading.

 

Most states allow you to own an AR pistol. But again, it’s important that you confirm your state and local laws to ensure you can own one before you start pulling out your wallet. Illegally owning an AR in areas where it’s prohibited could cost you more than your hard-earned money — it could cost you your freedom. 

As previously mentioned, there are a few rules that qualify an AR pistol barrel for legal ownership. The barrel can be shorter than 16 inches, you can’t have a vertical foregrip (it can be a handstop or angled foregrip), and you can have a pistol brace on your firearm to comply with AR gun ownership laws. The ATF does pay attention to the general length of an entire firearm, too. If a firearm is over 26 inches long with a barrel shorter than 16 inches long, it can have a vertical foregrip (but not a rifle stock).