parts of an upper receiver AR-15 bootleg

Parts of an AR-15: Upper Receiver

Firearms can be complicated pieces of machinery. In the history of gunsmithing, guns were notoriously hard and toilsome to make by hand because you had to have all of the component parts just right or you risked the possibility of your gun misfiring, causing severe potential harm. With the advent of the Industrial Revolution and machinery, guns became much easier to make. However, they still have a lot of crucial components that work together in order to function. Semi-automatic firearms have more parts than others simply due to the rapid-fire capabilities that make it so popular.


Bootleg Inc’s mission is to supply quality parts and information to those who want to build AR-15s. We offer almost everything you need, except for the lower receiver. From handguards and carriers to the upper receiver, you can customize your AR to fit your needs. All of our AR parts are made in the United States from the finest-quality metals constructed to last a lifetime. We offer a gentleman’s guarantee on exchanges and refunds. Below, we’ll take a look at the upper receiver parts of an AR-15 rifle. Shop our AR accessories today!


parts of an upper receiver AR-15 bootleg



Upper Receiver


The upper receiver is the top portion of your AR-15 and contains the barrel, forend, bolt carrier group, charging handle, and any AR accessories you want to mount on rails, such as a scope. The upper receiver attaches to the lower receiver to form your gun. The upper receiver can be customized for your AR-15 parts.




Of the AR-15 parts of your upper receiver, the barrel is arguably the most important part. The barrel of your gun is where your bullet comes out. It’s also where the acceleration of the bullet happens once the charge has been released after you pull the trigger. There are many different sized barrels of guns your AR-15 can have, and in general, the longer the barrel, the further the bullet will travel. You can also add in rifling to your barrel (grooves that are spirals in the interior). This makes the bullet spin when it comes out, making your shot more stable and accurate. For AR-15s, the barrel of the gun has to be at least 16 inches long or it becomes a short-barreled rifle, which is against the law. If you want to go shorter, you can have an AR pistol instead.

Bolt Carrier Group


This is the overarching name for all of the small components responsible for loading your AR-15 rifle. It’s job is to ensure that your bullets are fired correctly and that the spent bullets are then ejected from the chamber so that you can continue firing. There are many little components of the bolt carrier group that include the firing pin, bolt, cam pin, extractor, and gas key. These you can purchase all together, or you can buy these individually for the optimal in AR customization. Bootleg offers Our Four Position Adjustable Carrier that is a complete bolt carrier group and our 5.56 Assembled Nitride Bolt Carrier Group that is machines from 4140 and is nitride coated.


Gas Block & Gas Tube


Gas pressure is what moves your round out of the barrel towards your intended target. This pressure forces the bolt carrier group into the buffer tube, which causes the round to be ejected and a new one put in its place. Once you squeeze the trigger, the bullet leaves the barrel through the gas port. It goes inside the gas block, down the gas tube, and exits the bolt carrier’s gas key. Bootleg offers our Low Profile Gas Block to help your AR-15 rifle cycle quickly and seamlessly.


To get even more confusing, there are four different types of gas lengths that describe where they are located on your barrel. These are: rifle-length, mid-length, carbine-length, and pistol-length. Gas blocks are installed inside the handguard on the barrel, which connects to the block and the upper receiver. Bootleg offers our Bootleg SBN Gas Tube that is made from stainless steel for durability. We offer one in every gas length. Shop today!


Charging Handle


Every AR-15 has a charging handle. A charging handle’s function is to pull your bolt carrier group back in order to chamber a new round or to clear one that is not firing. You pull the charging handle back to release your shell and then reload another one. You can also load your first round using the charging handle when the bold is closed. The charging handle only moves when you tell it to, not while firing. Bootleg’s 5.56 Charging Handle is the best in custom AR parts. Made from 7075 aluminum and Type III hard anodized to keep it light but durable.


Forward Assist


The necessity of a forward assist is hotly debated amongst AR enthusiasts. A relatively new AR part added to your AR-15, a forward assist sits on the upper receiver, and it’s sole job is to help your bolt close all the way should it not want to.


Rail Systems & Handguards


As you can imagine, when you rapidly fire an AR-15, all that gas can heat up the barrel of your rifle quickly. Thus, rail systems and handguards have come along to protect your hands from the heat your gun generates and make shooting much more comfortable. Rail systems allow you to add AR accessories such as scopes, sights, flashlights, lasers, and more, while handguards add on another layer to the barrel for a better grip and heat protection. The beauty of both rail systems and handguards is that they come in a variety of shapes, sizes, colors, and styles to suit your tastes. They are great ways to accessorize your AR-15. Bootleg offers PicMod Handguards and CamLoc M-Lok Handguards machined from 6061 aluminum.


Ejection Port Cover


The purpose of an ejection port cover is to keep your weapon clean. It covers the ejection port to keep out dirt and debris from your bolt carrier group and your upper receiver when not in use. When you fire, it will open of its own volition. In order to ensure your AR-15 works optimally, you need to invest in regular maintenance and upkeep, such as cleaning your gun after firing and more. 



Bootleg specializes in making AR accessories and custom AR-15 parts, including parts for the upper receiver and the upper receiver itself. We offer a Bootleg Enhanced AR-15 Upper Receiver machined from 7075 aluminum, one of the strongest metals in the industry. We also offer our BLEM Bootleg MIL-Spec Complete upper receiver as well, complete with a 1913 rail for mounting accessories and optics. This upper receiver is discounted for a few blemish markings.


Bootleg works hard to bring you the best AR-15 accessories for your AR build. We love to help you customize your AR-15 or build one from scratch. These are great guns that are versatile, easy to use, and easy to put together. The upper receiver of your gun is crucial since it is where you place your hand to hold and aim your firearm as well as where the rounds are discharged. Visit our AR accessory store online today!

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