Upper Receiver Parts

Our wide selection of upper receiver parts allows you to customize your rifle in any way you choose. We offer parts such as complete upper receivers, muzzle devices, bolts and bolt carrier groups, barrels, handguards, etc. We deal with only high end US manufacturers who specialize in providing high quality parts that stand the test of time.

Best ar15 upper receiver parts

Upper receiver or just “upper” is the part that houses the barrel and muzzle device, bolt carrier group, charging handle, forward assist, and the dust cover. It is also the part to which the barrel and the upper receiver, handguard connect. There are three main styles of upper receivers: the A1 style receiver with a fixed handle on top, A2 style which also has a fixed handle on top, but with added rear sight with elevation and wind adjustments and the A3/A4 style often called “flat top” receivers. The flat top, or rail, allows you to mount any type of scope or sight as well as other accessories onto your upper receiver and as such it is the most popular variant. When choosing an upper and a barrel to go with it, pay particular attention to the type of feed ramps each have. A1, A2, and A3 receivers often have standard feed ramps and A4 has the colt extended M4 ramps. The difference between these styles is how deep they are cut into the barrel extension and the receiver. Ideally you want your receiver and the barrel to match or  you may run into feeding issues. Our selection only includes receivers and barrels with the M4 style feed ramps so if you buy all the parts from us, they are guaranteed to match.

The barrel is one of the most important parts of the rifle as it is the part that directly affects how accurate your rifle will be. They come in a huge variety of different calibers, lengths, materials, twist rates, styles, finishes, coatings, etc. For more information visit our Barrels page where we talk about all these things in more depth.

Bolt carrier groups and specifically bolts themselves are the second most important part of the rifle as it is the part that is most likely to fail. When deciding which bolt to get there are a several factors to take into account. A quality bolt must be made with either Carpenter 158 steel or S7 steel as it needs to repeatedly and reliably sustain high pressures. They also need to be MPI (Magnetic Particle Inspected), HPT (High Pressure Tested), and shot peened. There are also several things to consider when it comes to bolt carriers. Different carriers have different profiles and different finishes. A high quality bolt must have a properly staked gas key. Go to our Bolt Carrier Groups and Parts page for more information about bolts and bolt carriers.

Handguards come in a variety of shapes and sizes. Two main types are drop in and free float systems. Drop in systems are affixed to the upper receiver at two points, and free float handguards at only one. Which one to choose is entirely up to you, but it’s important to keep in mind that free float systems offer better accuracy at longer ranges.

Muzzle devices are mostly personal preference as they are designed to protect the crown of the barrel, which can be easily damaged if the rifle is dropped with no muzzle device attached. There are two main types of muzzle devices: flash hider and muzzle brake. Flash hiders do what the name implies; they reduce the flash signature of your rifle. They are quieter than muzzle brakes, but they offer no other benefits. Muzzle brakes offer a different advantage at the cost of being very loud. They offer increased accuracy by directing the gases in a particular pattern that helps reduce barrel travel allowing you to keep your rifle on target more consistently. There is also a third type of muzzle device which is considered a hybrid of the two style and supposedly provides the benefits of both. Although many of these are excellent muzzle devices, the claims are hard to prove. Unfortunately, all too often most muzzle devices are chosen based purely on aesthetics.

Gas blocks and gas tubes are parts used as part of the gas system which cycles the rifle. Depending on the handguard you choose and the general set up of your upper receiver, you may use either a low profile gas block or a railed gas block. These can come either made of steel or aluminum. If you decide to go with a low profile gas block, we recommend avoiding aluminum ones as they tend to be lower quality and thus fail more often. Gas tubes come in different lengths from pistol to rifle lengths. They transport the gas from the barrel to the gas key on the bolt carrier group causing it cycle the rounds. All our parts are made and assembled in the US and all meet or exceed all mil-spec standards.