Upper Receiver

The upper receiver is the part that contains the bolt carrier group and charging handle. The barrel and the for-end are also attached to the upper receiver.

Lower Receiver

The lower receiver is the part of your rifle that is generally considered to be the firearm itself (rather than just a component). For this reason, it is one of the most legally regulated parts of an AR-15. On AR-15s, the lower receiver is where you’ll find your weapon’s serial number.

Bolt Carrier Group

There are a number of components inside the bolt carrier group, including the firing pin, bolt, cam pin, extractor and gas key. At a very basic level, the bolt carrier group is responsible for loading your rifle, making sure bullets are fired correctly and ejecting spent rounds from the chamber. You can either buy a bolt carrier group that has been preassembled, or you can choose the parts you want individually and put it together yourself.

Charging Handle

A charging handle is the part that pulls your bolt carrier group to the rear when you need to chamber a round or to clear a malfunction. If a round doesn’t fire as it should, you can simply pull on the charging handle to release the faulty shell and reload a new one. A charging handle also lets you load the first round of a new magazine if the bolt is closed. When you fire your AR-15, the charging handle remains stationary.

Gas Block & Tubes

Your rifle relies on gas pressure to operate in the way that it’s designed. After you fire your AR-15, gas pressure forces the bolt carrier group into the buffer tube, a process that facilitates the ejection of a used round and the chambering of a new one. After you fire your rifle, gas moves behind the bullet that’s leaving the barrel and moves through the gas port. It then goes inside the gas block, down the gas tube and leaves through the bolt carrier’s gas key. There are four different types of gas lengths: rifle-length, mid-length, carbine-length and pistol-length. These different gas lengths are named after the location of the gas port on your barrel. Generally, your barrel length can be determined by reading the packaging or description. For the most part, gas blocks are installed on the barrel, inside the handguard. The gas tube connects to the block and the upper receiver.

Trigger Groups

You can’t fire your rifle at all without a trigger. And you can’t fire it accurately if you don’t have a trigger pull weight that feels comfortable to you. The trigger group consists of the trigger and the hammer of your AR-15, as well as other necessary housing components. Like any other piece of your weapon, you can customize the trigger of your rifle to your exact specifications. Triggers can also play a pivotal role in your shooting experience. You’ll enjoy more accuracy and faster firing rate when you’re using a lighter trigger. But keep in mind that a light trigger might easily lead to negligent discharge (ND) due to the ease of firing. That is the reason why Military and Law Enforcement use heavier trigger on their duty weapons for liability reasons. Everyone has their own opinion on what constitutes a ‘light’ trigger, and our rule of thumb is that any trigger lighter than 4 lb is considered light. The United States Army is using 8-9 lb triggers on their M4s.

Barrel

When it comes to ensuring the best possible shooting experience, the barrel of your rifle might be the most important part of your upper receiver. After all, your barrel will play a huge role in your accuracy on the range or in the field. Barrels come in a variety of lengths and weights based on your needs. Whichever model you select will have a direct impact on the length of the gas system you’ll have to use to cycle your rifle. It’s important to keep in mind that, in most cases, your barrel should be at least 16 inches long. If it’s shorter than that, your weapon becomes a short barreled rifle, which is against the law unless you have the proper paperwork and federal tax stamp. But there are couple ways to have a barrel that is shorter than 16 inches on your AR-15 without any paperwork. One popular choice is to build an AR pistol, or you could pin and weld a 1.5” muzzle device on a 14.5” barrel permanently to make the overall barrel length 16 inches.

Grips

To ensure the best shooting experience, you have to have the firmest grip on your rifle. When it comes to getting the best hold on your rifle – and therefore the most accurate shots – you’ll have to consider both of the following: Foregrips - Both of your hands play a crucial role in determining how accurately you fire your rifle. In addition to getting a good pistol grip with your trigger hand, you might also need a strong foregrip to ensure that you’re shooting a steady gun. Foregrips can be installed vertically or angled, depending on your preference. Choose whichever grip is most comfortable for your own shooting style to fire most accurately, and you’ll naturally give yourself an edge against your competitors. Pistol Grips - Your trigger hand has the final say as to when a shell is fired. That’s why you need to make sure that your trigger hand has the best possible grip on your AR-15 as possible. The pistol grip attaches to the lower receiver, giving you a firm handle of your rifle. You can choose among a multitude of grips, finding the accessory that feels best in your hands. The better your grip, the bigger your advantage.

Lower Parts Kit

Many gunning enthusiasts enjoy putting their rifles together themselves. After all, the better you know the anatomy of your AR-15, the easier it will be for you to customize it to your exact specifications and to identify the cause of malfunctions. While you can certainly buy a completed lower receiver group, you can also buy a stripped one and put it together yourself with a lower parts kit. What’s better than shooting with precision than with a weapon you assembled yourself?

Butt Stock

How your rifle rests on your shoulder plays a major role in your overall gunning experience. It’s easy to be distracted if you’re uncomfortable while aiming at targets. In the simplest terms, the butt stock is the part of your AR-15 that connects to the rifle’s firing mechanisms. Like most other parts of your gun, you can choose among a wide array of butt stock options to build your rifle to your exact specifications. As you begin your search for the butt stock that’s right for you, the component will fall under two categories: fixed stock or collapsible stock. While collapsible stocks help you place the perfect amount of distance between your shoulder and your rifle, fixed stocks are more formidable and can help counter heavier front ends.

Buffer Tube

As part of your rifle’s recoil system, the buffer helps absorb a lot of that kick, making your shooting experience more seamless. The right buffer can give you an edge over your competitors, as you’ll be able to shoot accurately for a longer period of time. Buffer tubes house both the buffer and the buffer spring. Together, these components slow down the faster parts of your rifle’s action, protecting both themselves and the frame. This ensures that the integrity of your weapon remains intact. With a pistol buffer tube, you’re able to build a short barrel rifle without having to obtain the usual paperwork because the AR will classify as a pistol. This allows you to use any length of barrel on your rifle – even those that are shorter than 16 inches.

Muzzle Brakes

Muzzle brakes - The AR-15 is capable of shooting many rounds quickly, but firing rapidly can result in muzzle climb as the elevation of barrel increases from your weapon’s recoil. Whether you’re hunting or shooting in competition, when you shoot your rifle, you need to be able to shoot it accurately. The recoil of the rifle can prevent you from taking your follow up shot accurately. Muzzle brakes are proven to reduce recoil by as much as 50 percent. These components vent gases horizontally, giving you a clear line of vision while enhancing the shooting experience. Because the gases are vented horizontally, many shooters consider it courteous to avoid using muzzle brakes in a crowded range environment, as the gases can interfere with the experience of nearby shooters.

Ejection Port Cover

Ejection port cover - To make sure that your weapon functions as flawlessly as possible, you need to keep your AR-15 impeccably clean. That’s exactly where an ejection port cover comes into the equation. When it’s closed, the ejection port cover will prevent dirt, dust and other debris from dirtying your rifle, as it keeps both the bolt carrier group and the upper receiver clean. The component only has one function – to be open or closed – but it’s an important one. You’ll have to close the ejection port cover on your own, but it will also open up on its own when the bolt carrier group moves to the back.

Magazines

You need to hold your bullets somehow, right? That’s what magazines are for. You can get different sized magazines, but it’s important to keep in mind that laws for the size of magazines can vary from state to state. On top of that, because of the political climate, you never know when these kinds of laws might change. It’s important to stay in the loop about these rules, so you can make sure you’re gunning within the confines of the law.

Scope Mount

The rifle scope mount is an important component for rifles and long-range guns. It is the base used for mounting the scope. The best of rifle and scope combination would be rendered useless without a set of reliable and sturdy scope rings and bases. If the scope mount does not match the mounting system of the rifle or if it is offset even by a fraction of an inch, it could completely throw your aim off and result in a miss.

Riflescope

The Riflescope is an optical sighting device based on a refracting telescope. It is equipped with some form of a referencing pattern mounted in a focally appropriate position in its optical system to give an accurate point of aim.

Lights

Lights for your firearm.

Laser Sights

Laser to provide aiming for your firearm.

Holster

A holder for carrying a handgun or other firearm, typically made of leather and worn on a belt or under the arm.