A Brief History of the AR 15

The AR-15 semi-automatic rifle has an unmemorable history. It was designed in 1956 by Armalite. In 1959, the patent to the AR-15 was sold to Colt. It was marketed to civilians as the counterpart to the military fully automatic M4 rifle. 1977, the patent was allowed to expire, and the AR platform became open-source. This means various companies began to offer and construct AR-15-style rifles.

Today, the AR platform has become one of the world's most recognized and iconic rifles. It is manufactured by large and small companies across the United States and the rest of the world. The AR 15 has also become one of the favorites for garage builders.  AR-15 Parts and accessories are readily available from hundreds of online suppliers and sellers.

The rifle can be built and customized with only a few tools and by watching YouTube videos. The main thing to remember is to purchase your lower receiver from a dealer with an FFL. The only part of an AR-15 considered a gun must be registered in the lower receiver. However, when picking out pieces, please check with your local regulations. The length of the barrel is the primary regulated assembly configuration, not only the main one.

Before you get your hands dirty building your AR15, take a minute and learn the essential parts of the rifle. We have compiled a significant AR 15 Parts Diagram that lists all the AR 15 Parts you need to know.

AR 15 Lower Receiver

The lower receiver is the part of the rifle that houses the fire control group, magazine well, and pistol grip. It can be made in several ways, the two most popular being forged or machined. Forged lowers are created by hammering thin metal into their final shape. Billet lowers, on the other hand, are machined into their body using a mill to remove material from a solid piece. Forged receivers tend to be slightly stronger. However, billet receivers tend to be lighter in weight.

As stated, the lower receiver is the only part of the AR-15 legally considered a firearm. It contains a registered serial number, and specific regulations govern its purchase.

You must buy the missing lower receiver parts if you purchase a stripped lower receiver. These include a trigger assembly, trigger guard, magazine catch/release, bolt catch/release, safety selector switch, grip, takedown pins, receiver extension (buffer tube), buffer, buffer spring, and buttstock. You can purchase these as a complete AR-15 lower-build kit or search for each separately.

AR-15 Upper Receiver

The AR-15 upper receiver houses and protects the components on the top of your rifle. It can be a flat top or come with an integrated carry handle. A flat-top receiver typically has a Picatinny railing across the top. The carry handle receiver has a handle and rear sight assembly on top.

The upper receiver can be forged, billet, or cast. Cast receivers are the lightest option, although they are also the weakest. You can purchase a  stripped upper receiver, which only contains the upper receiver and will require more parts.

A great option is to purchase a  complete upper assembly. Parts in the upper receiver group that you must attach to a stripped upper include a forward assist, dust cover, charging handle, barrel, muzzle device, handguard, and bolt carrier group.

The easiest option is to purchase a complete rifle build kit, which includes everything you need to build your rifle except the lower receiver. It would be best to buy that piece from your local FFL Dealer.

Gas System

When the round is fired, it is propelled by the high-pressure gas generated from the gunpowder explosion. The AR 15 uses some gas to eject the spent round and load a new game into the chamber. It uses a gas system comprising the gas block and gas tube. The gas systems have several different lengths depending on which configuration you are putting together. The sizes are pistol (shortest), carbine, mid-length, and rifle (longest). Remember that the gas system components and the gas port on the barrel need to match.

AR 15 Furniture

After you've installed the essential components of your AR-15, it's time to focus on the furniture—the parts of the rifle you hold for support and control. This includes the stock, grip, foregrip, and handguard. These pieces provide comfort and stability while shooting and allow you to customize your rifle to fit your style and preferences. Whether you're looking for enhanced ergonomics, better control, or a tactical look, choosing the right furniture can make a big difference in your AR-15's performance and handling.

Grips

Grips come in varying sizes, textures, and even angles. You should pick your grip based on what feels best for you. But to get started, the best action is to buy mil-spec and make any changes after firing a few hundred rounds and discovering what you wish was different. See what's available in stock now:  AR 15 Grips.

Stocks

When choosing a stock for your AR-15, plenty of options fit your needs. You can find adjustable stocks for custom length, lightweight models for easier handling, and even collapsible stocks for better portability. Some stocks offer built-in storage compartments, many in various colors to match your style or tactical gear. For a wide range of options, including complete kits, check out AR-15 Stocks and AR-15 Stock Kits. Whether you're looking for functionality, comfort, or aesthetics, there's a stock to suit every shooter.

Handguards

Handguards do more than keep your hands from touching the barrel. They are a convenient mounting point for furniture and accessories. When choosing a handguard, remember the length and the mounting style. Handguards come with Picatinny, M-Lok, and Keymod mounting points. They will all have different benefits and drawbacks, so it is a matter of personal preference.

Crafting the Perfect AR-15: Your Journey Begins Here

Building your ideal AR-15 rifle is all about the right parts and accessories, such as scopes, straps, lights, sights, or tools that enhance your rifle's performance and usability. The possibilities for customization are endless, and now it's time to take that first step.

Start your journey with Black Rifle Depot, where you'll find everything you need to bring your AR-15 vision to life. With top-notch customer service, live inventory, competitive prices, and fast shipping, Black Rifle Depot is your trusted source for AR-15 parts and accessories. Get started today and craft the perfect AR-15 to fit your needs.