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Guns come in various shapes and sizes. For many of us, our guns come second in the list of things we love most in life. If that's a perfect description of you or a point you want to get to soon, then this article is for you.
It’s an important thing to understand your gun in its entirety to not only make the best use of it, but to also make it easy for you to take care of it to maximize durability. The best way to understand your gun and how it functions is to know its constituent parts.
In this article, we will explore the various parts of the AR-15 so it's easy for you to learn them by heart. This information will come in handy whether you are buying a complete, ready-to-use gun or customizing on your own part by part. Let's arm you with facts!
What Are the Parts Of an AR-15 and How Many Parts In an AR-15?
An AR-15 consists of two main sections: the upper receiver parts, and the lower receiver parts. The two parts are held together by two pins. When the two pins are both pushed out, the parts are separated. If the pin on the rearmost side is pushed out, the upper receiver tilts forward to allow for field cleaning.
Depending on the mode of counting the parts of the AR-15, the number will be 100 using a condensed counting approach, and 140 using the expanded approach. The condensed approach counts several related parts as a batch, while the expanded approach counts every single part on its own.
AR-15 Parts Diagram
To have a clear understanding of the AR-15, please refer to the picture below. There are several versions of the gun. This is just one of them. Note that the letters "AR" do not stand for "automatic or assault rifle". They stand for "Armalite Rifle" because the original maker was known as ArmaLite, Inc before they sold the design in 1959 to Colt.
Upper Receiver Parts
The upper kit consists of the following parts:
Barrel
Charging handle
Dust cover
Forward assist
Gas block
Handguard
Bolt Carrier Group
Gas tube
Upper stripped receiver
Muzzle group
Bolt Carrier Group
The bolt carrier group comprises the bolt carrier with key and key screw, bolt catch with pin, spring, and plunger, and the bolt ring. The gas key, firing pin, cam pin, and extractor also come in this section. The bolt carrier group works to load the gun, fire bullets the right way, and extract used shells out of the chamber.
Muzzle Group
The muzzle group has devices like compensators, flash hiders, and muzzle brakes. Compensators come in handy in countering muzzle climb in case you are firing rapidly. As such, you are able to maintain more on-target shots.
Muzzle brakes help reduce gun recoil so you can take accurate follow-up shots when firing rapidly.
Afraid shooting might give your position away or interfere with your sight plane? The flash hiders reduce the muzzle flash effect, a light flash which results from the combustion of gunpowder as bullets eject from the barrel.
Barrel
The barrel is among the most important features of the AR-15, and its length should be at least 16 inches for best shots. It may be made of treated steel which lasts for a longer time, or stainless steel, which offers more accuracy.
Lower Parts Kit
The lower parts kit consists of the trigger parts, bolt release, magazine release, hammer parts, safety selector, among others. The trigger parts include the trigger, trigger spring, guard, and two roll pins - one on the front and the second one on the rear.
The hammer also has a spring and pin. The magazine release comes with a release button and magazine catch with its spring. The pistol grip has a screw and lock washer. The safety selector features a spring and detent.
Lower parts kits are not identical and you may opt for a kit with lesser items to avoid buying extra parts that you may never use.
How an AR-15 Works
Once the cartridge of an AR-15 is chambered, the bolt rotates and locks to enable it to withstand the massive pressure caused by gunpowder combustion. After the cartridge fires, the bolt rotates in the opposite direction and pulls back to allow for the extraction and ejection of the spent case, after which a new round is chambered.
In the barrel, immediately the bullet goes past the gas port, some of the hot gases enter the gas tube bolt carrier group. Through the bolt carrier key, the gases flow into the expansion chamber and the pressure in it builds up. This pressure causes the bolt carrier to push back, making the two holes on the side go past the C rings that are in the tail of the bolt. This movement of the holes causes the hot gases to vent.
With the bolt carrier still pushing backwards because of the inertia, the cam slot offsets the bolt lug, making the bolt rotate back into the unlocked state. The bullet is by now out of the barrel and the pressure reduced to a safe level.
The pulling back of the bolt from the breech as the bolt carrier pushes backward due to the inertia causes the extraction and ejection of the spent shell. To reload the cartridge, the recoil spring which has been compressed by the bolt carrier group propels the bolt carrier forward once more to slide a new cartridge off the magazine and chamber it. The cam slot engages the bolt lug to rotate them and lock the bolt, bringing the process to full-circle.
Conclusion
Whether you are buying a complete rifle or custom-building your AR-15, this article sheds light on the parts of this celebrated rifle with an overview of how it works so you are not only armed with a firearm but facts as well. Assembling the rifle on your own can be fun for the adventurous gun enthusiast, so be sure to check what parts come with the new kit you are buying. If you want to do it faster and easier, we recommend that you pick a ready-to-shoot rifle and plan to learn its parts by heart.
People Also Ask
How about a brief look at the main questions people ask about the AR-15? This section will add to your knowledge of the gun and also answer some of the questions you may have about it.
What Part Of the AR-15 Is Considered the Gun?
The lower receiver is the part of the AR-15 that is considered as the gun. As such, it becomes one of the parts of the gun that are highly legally regulated. The gun's serial number is found on the lower part. The tight regulation means that the lower component ships to licensed firearms dealers, rather than being available in stores as an over-the-counter item.
What Parts Are Interchangeable Between AR-15 and AR-10?
Although the AR-10 and AR-15 have some basic differences, the following parts are compatible between the two guns:
- Magazine springs
- Magazine release buttons
- Buffer detent
- Buffer tube
- Triggers
- Trigger springs
- Disconnector
- Disconnector springs
- Bolt catch roll pin for the Armalite version
- Hammers
- Hammer springs
- Safety selectors
- Buttstock components
- Pistol grips, although certain versions may need a spacer
Which Part Of an AR-15 Is Registered?
The lower receiver of the AR-15 requires registration as it is the officially recognized and legally controlled component. You will be required to have a valid certificate to prove ownership of the gun. The serial number, which is unique for every gun, is the key identifier. Please make sure that you receive this certificate when you buy this weapon.
How Much Are AR-15 Parts?
It will cost you between $900-$1550 to build a high-end AR-15. The price is dependent on the dealer or store you are buying the parts from, with some selling parts at higher prices when purchased individually. To obtain a friendlier price if you are on a budget, consider buying the complete kits as they usually cost much less from $600. The downside to this cheaper option is that you might end up with some parts that you may never use.
What Parts Wear Out On an AR-15?
The parts of the AR-15 most vulnerable to wear are the gas tube, gas springs, extractor, extractor spring, firing pin, bolt, and ejector spring. The other parts most likely to wear out are the hammer, disconnector, and trigger springs.
How Hard Is It To Build an AR-15?
Building an AR-15 is an easy and fun task if you have the right parts and ample knowledge of what part fits where and with which other ones. Once you have all the necessary components, you can easily assemble the gun using the user manuals obtained at the point of purchase. You can also refer to online sources like YouTube and gun websites for tips on assembling. With constant practice, building your rifle perfectly won't be hard. Keep practicing.
What Part Of the AR-15 Not Sold In a Kit?
Since the lower receiver is highly legally controlled, this part is not sold in kits. It has to be shipped to licensed firearm dealers. It's worth noting that a parts kit features the components of a firearm, but without a receiver. As such, it is legal to sell these parts together, while the receiver ships separately to allow for the required regulation on it.
What AR-15 Parts Make It Full Auto?
The AR-15 is semi-automatic. Let's not get so deep into the nuts and bolts of automating your gun, but here's a brief overview.
You will need to use the S.W.D Auto Connector (popularly known as the "lightning link".) You can also use a drop-in auto sear, popularly known as the DIAS.
However, you have to be extra cautious because this is highly regulated, and you may only be able to do it by registering as a federal firearm licensee. If you quit this licensing, you will be required to destroy, sell, or turn in the guns you have made in the past. You may want to try automating your AR-15 if you have the patience for the lengthy legalization process and lots of extra bucks to buy the additional parts.