What is an AR-15 Upper receiver?

The receiver of an AR-15 is broken into two main parts, the upper and lower receivers. The design of the AR-15 is this way so that the main components of the firearm can be broken into two separate housing units, making maintenance easier than virtually any other gun on the market. The AR-15 upper receiver is one part of the AR-15 that is available to consumers, and because of its design, has  some very unique features that distinguishes it from other platforms. 

What is an AR-15 Upper Receiver?

The AR-15 has one of the simplest designs in modern firearms. Where many are composed of many small parts, and often made optimal for production, the AR15 is made with basic components and is optimized for easy assembly/disassembly. 

The Upper Receiver:

The upper receiver of the AR-15 controls a few of the core functions/ parts of the system. The AR-15 upper receiver houses the ejection port, giving way for spent cartridges to escape. The bolt carrier group is also housed in the upper receiver, which is responsible for cycling the rounds into the chamber, and out after firing. The gas system’s core functions take place in the upper receiver, meaning that most of the movement for the function of the AR-15 is done in the upper receiver. 

The AR-15 upper receiver has one  component, traditionally, that the community either views as necessary or unnecessary, and that is the Forward assist. It was designed as a button that would manually push the receiver forward if the action could not automatically cycle. There are not many situations where this is necessary as most times firearms  are shot, the conditions are ideal. The forward assist is a combat addition to the AR-15 upper receiver.

Can you buy an AR-15 Upper receiver without an FFL?

Of course you can! The AR-15 upper receiver, and even AR-15 upper assemblies can be purchased without an FFL because they can be sold separately from the AR-15 lower receiver, the part legally considered a firearm. 

The AR-15 upper, because it is not connected to the lower, is not actually a part of what makes the AR-15 a firearm. That is all for the lower receiver, or the part of the receiver that houses the fire control group. Funnily enough, it is not the fire control group itself that makes the lower a firearm, but the port for the fire control group on the lower that makes it a firearm. 

The upper receiver or AR-15 upper assembly  does not have a component that directly correlates to the firing of the gun, and that is why it is not considered a firearm. That means buying one is as simple as getting online and hitting check out. 

How Long are upper receivers?

AR-15 upper receivers are about as long as the lower receivers. However, in the AR-10 and the AR-9, there are slight differences to the specifications. However, the length for these platforms will not change. When buying an AR-15 upper assembly, the length is dependent on the barrel. AR-15 pistol upper assemblies must be under 16 inches, while rifle upper assemblies must be 16 inches or over.

Is it difficult to assemble an AR-15 Upper receiver?

No, it is not difficult to assemble an AR-15 upper receiver Here are the main parts of an AR-15 upper assembly.

Barrel and Barrel nut: On the barrel, the gas block and gas key must be installed by tightening two screws. The barrel is connected to the upper receiver of the AR-15 via the barrel nut.

The forward assist. On some AR-15 upper receivers, there is not a section for the forward assist to be installed. However, it is a very simple assembly that involves inserting the spring and button and securing it with a punched-in roll pin. 

The bolt carrier group and charging handle are the easiest parts to remove than any part on the AR-15. All you have to do is slide the charging handle, followed by the bolt carrier group into the receiver cavity, and voila. 

The dust cover, which is also scarcely necessary, is installed with a tiny spring, the flap, and a hinge which the door can swing on. 

These are all of the main components that need to be installed on an AR-15 upper receiver in order to make a functioning AR-15. Purchasing these

Where to buy AR-15 upper receivers?

AR-15 upper receivers can be bought from almost any online gun store that sells AR-15 parts. Because they typically milspec, you will not have to narrow your search very much at all. AR-15 parts are found on almost all of the top online gun stores and can be assembled from the comfort of your own home. 

Online gun store is normally, the number one outlet for purchasing AR-15 parts. The items, if not  FFL items, can be sent directly to your own home. There are a plethora of parts to choose from that include different finishes. You can buy the parts either separately or a part of a build kit with the parts already assembled. 

The AR-15 is one of the cheapest rifles money can buy, especially since you don’t have to purchase from name brands to get the same quality. All AR-15 parts are machined to the same specification, so all it takes to get a glimpse of the quality of these parts is the review section of the company you are thinking about buying from. 


The AR-15 upper receiver is one of the most easily customizable parts of the AR-15. The upper receiver even holds the handguard, which is the one thing that most attachments are installed on. Upper assemblies can be bought online and sent straight to your house with the click of a button. There are plenty of customization options, from different furniture to whole new finishes. The AR-15 upper receiver is easy to maintain because. You can find AR-15 uppers from almost anywhere online for a great price. 


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