Upper Receiver Group
Upper Receiver
The receiver itself is a simple part that holds many other critical parts, such as the front attaching handguard, barrel, forward assist, charging handle, AR scope, and bolt carrier group. As long as all the standard specs are within it, the receiver doesn’t play much of a role in reliability or durability.
Barrel & Barrel Nut
Based on your objectives, even relatively inexpensive barrels can exhibit remarkable precision. If you desire a highly accurate rifle, investing in a high-quality barrel is crucial. It’s worth noting that the barrel plays a paramount role in achieving accuracy and precision, and therefore, every component should be of exceptional quality.
Various sizes, rotations, and shapes of barrels are available in a diverse selection. Refer to The Best AR Barrels: Length, Material, and More to find comprehensive information about this topic.
The barrel nut is a substantial screw-on nut that maintains the barrel linked to the upper receiver. Straightforward, long-lasting, and sturdy.
Gas Block & Gas Tube
The firearm operates by cycling the bolt carrier assembly and directing gas into the gas block, which then travels through the gas tube (connected to the gas block) and exits the barrel through the gas block located above a gas port that is drilled near the muzzle. The gas block is securely attached to the barrel.
Gas blocks and tubes are simple parts that rarely fail for any reason. If you want to get fancy, the gas block allows you to regulate how much gas is allowed through the carrier bolt. This also means less recoil and less felt strength when cycling the rifle.
An enduring choice that ensures an unfailing front sight is the Front Sight Block, which serves as both a front iron sight and a gas block, on the opposite side of the complexity range. Currently, these are not as widely favored as they impede a barrel from floating freely, but the barrel remains unattached to anything other than the gas block and barrel nut/receiver, with no interaction.
In general, it is preferable to have a longer length. Rifle is superior to mid-length, carbine, and pistol. It is important to mention that there are various sizes available for your gas tube.
This system results in reduced wear on internal components and softer firearm recoil, as it decreases the pressure and gas within the tubes, thereby prolonging the lifespan of the gas.
However, it is not always feasible to do so, I consistently suggest acquiring the longest gas system that is compatible with your barrel. Nonetheless, the gas tube of your AR-15 is constrained by the specifications of the barrel.
Manufacturers know how much gas is needed for each barrel to work correctly in the AR-15 system, and they have figured out the science of how gas works over a long period of time. You don’t need to worry about that, but it is important to note that such a gas system is quite long.
Handguard
If there are any unwanted fragments and you happen to be positioned between the last line of defense, a good handguard might be necessary. A good handguard not only shields you from catastrophic failures and heat, but it also provides a place for you to put your hands. Wrapping themselves around the barrel and connecting to the upper receiver, handguards ensure that they receive the proper respect.
Not only that but a good AR-15 handguard will also give you room and mounting points for lights, grips, sights, and more.
Check out our article on Picatinny, M-LOK, and KeyMod for additional information!
Muzzle Device
The device relies on the impact created by gases escaping in various ways, attaching to the muzzle end of a barrel. It covers a wide range of suppressors, compensators, brakes, and flash hiders.
In low-light, to help preserve your vision, the muzzle flash is sent away from the shooter by flash hiders directing the gasses.
Compensators redirect gases upwards to assist in pushing the rifle downwards and decrease muzzle flip.
Brakes send gases backward and/or to the side to help reduce felt recoil. Brakes and compensators are often combined into one device.
The suppressor allows the gas to cool significantly, thereby reducing the sound of the gunshot. Suppressors are large cans that contain a volume of space for the gas to cool and expand before exiting.
Bolt Carrier Group: Bolt Carrier, Bolt, & Firing Pin
The most important aspect of your AR-15 is the long-term durability and reliability of its engine. The Bolt Carrier Group (BCG), which includes components such as the retaining pin, cam pin, firing pin, bolt, and carrier itself, needs to function properly for the entire system to work effectively.
Other manufacturers may provide captivating characteristics that can be combined and selected individually with carriers and bolts. Nevertheless, typically, a BCG is purchased as a comprehensive entity and encompasses all the necessary components.
Forward Assist
Nearly all AR-15 Standard upper receivers will have a forward assist on the side of the receiver that allows the bolt carrier group (BCG) to be pushed forward into battery. The forward assist acts to assist the teeth on the BCG for pushing the BCG forward into battery. This forward assist is either a critical or completely useless part of the receiver, depending on the context.
Upper receivers lacking a provision for the installation of a forward assist are commonly known as “slick side” receivers.
I will first go ahead and say that I don’t like rifles on the slick side, but I will leave the debate on the merits of assisting comments to be argued in the forward context.
Charging Handle
By attaching to the front end of the BCG and extending out the rear of the upper receiver, how one manually cycles the rifle in a normal AR-15 is.
Otherwise, these suppressors are commonly useful if you’re running a shooter – they redirect or cut excessive gasses and often include ambidextrous handles to provide a nicer pull and smoother feel. Upgraded models will make the charging handle feel even better, but a normal handle is good enough.
Lower Receiver Group
Lower Receiver
The lower receiver, oddly enough, is a very simple and unimportant part of the AR-15, as it doesn’t really add or take away anything from the overall reliability and durability of the rifle. However, it holds everything together and can be built with features that contribute to its overall performance.
Frequently, the primary distinctions among AR-15 lowers are merely the engravings on the exterior and the visual appeal of the layout.
However, there has been a major push in the last few years for truly ambidextrous controls, making it much easier for most shooters to operate the lower receiver, which houses almost all of the rifle’s controls.
However, the bolt catch is considerably more difficult, while the safety and magazine release can effortlessly be added to any regular mil-spec lower. To truly achieve ambidexterity, a lower must possess an ambidextrous safety, magazine release, and bolt catch.
Ensure that you select a lower receiver that already has a bolt catch specifically designed for ambidextrous use if you have a genuine interest in an ambidextrous lower. Typically, this entails the need to re-mill the lower and install an ambidextrous bolt catch.
Fire Control Group: Trigger, Hammer, Disconnector
It serves as a trigger, but for simplicity’s sake, it is technically only one component of the fire control group. In most cases, they are simply referred to as “triggers”.
If we want to be technical, the trigger is the part that hangs out of the lower and prevents the firing pin from actually smacking the cartridge and connecting both the disconnector and the hammer. The disconnector sits on top of the trigger and when you pull the trigger, it dumps the round from your AR-15, preventing the gun from going bang.
On an AR-15, there are numerous post-purchase triggers that effectively enhance the pull and break, but any military-standard trigger is sufficient to manage with.
If you desire a precision rifle, a superb trigger is the second most crucial component to focus on.
Enhance the rate of combustion and significantly expedite the ignition process while retracting and pulling back the trigger, resulting in a firing mechanism that activates binary-like components. This not only adds an element of excitement but also allows for a more enjoyable experience.
Buffer Tube
It is a tube that holds the buffer, otherwise known as a buffer tube. You can fold it and add something like the Tactical Law Folder. That’s what it does. That’s what it is.
They really come in two major flavors, alright – rifle and carbine. While the rifle stock uses tubes designed for things like an A2 stock or any other stock, the carbine stock uses the style of the rifle stock but is normally adjustable, unlike carbine gas systems (carbine stocks are not designed for carbine gas systems).
Buffer Spring & Buffer Weight
The BCG is returned to the upper receiver after each shot by the spring and weight located within the buffer, effectively reducing the recoil of the BCG.
If you’re interested in fine-tuning your rifle for maximum reliability and minimal recoil, adjusting the buffer weight and spring strength can be effective methods to achieve that.
Going too heavy can cause the rifle to short stroke. Too light will cause excessive wear, more recoil, and induce strange malfunctions.
Make sure to use the appropriate stock and tube that matches the type of rifle or carbine you have. There are plenty of different flavors of tubes, as well as springs and weights.
Buttstock
The quality of a good buttstock can greatly impact how comfortable and stable your rifle feels in your hands, whether you are using a large precision rifle stock or a small carbine stock that rests on your shoulder.
Do not hesitate to experiment with your choices and discover what suits you most.
Grip
Depending on your requirements, there are numerous superior designs, but the conventional milspec A2 grip is not subpar. Grips are as individual as spectacles and are available in a wide range of variations. Indeed, you accomplished that. Were you anticipating it? You were not. It is what you grasp onto.
The hands that I want are also larger than the ones that are normal. I really like the grip that is very grippy due to the aggressive stippling.
If you’re a pistol shooter, what do you think about the characteristics that match the grip of a pistol and the look and grip of an AR?
Safety Selector
The rifle is off safety when you pull the trigger, and the rifle is on safety when you don’t pull the trigger. Some people prefer standard rifles, while others prefer ambidextrous rifles like myself.
Takedown Pins
Don’t be one of those weird people who spend $60+ on titanium pins just to hold the lower and upper complete together. Instead, simply get the milspec ones.
Bolt Release
Technically, the bolt release both unlocks and secures the bolt. I’m not sure why they are simply referred to as releases.
Once you are loaded up, a fresh round will be inserted into the chamber and the BCG will move forward. To reload effortlessly, simply press the bolt release, which prevents the bolt from advancing when there is no more ammunition to collect and allows your BCG to go in either direction.
There are a variety of sizes and designs to choose from, but I prefer a regular milspec one.
You can invest in a luxurious one, but I’ve never seen them do anything that an inexpensive one doesn’t do.
Magazine Release
If you want to stay in touch with a magazine you like, you will still need one. And if you want to get an AR-15 magazine, you will need one as well.
Unless your magazine release is ambidextrous, there is nothing that a fancy one does differently than a regular one.
I am a big admirer of ambidextrous magazine releases and they are extremely simple to install.
Wrapping Up
And there you have it – all of the components of an AR-15!
I hope that I helped you get introduced to the most popular sporting rifle in America. Let me know in the comments if you have any questions.
In the United States, please make sure to check out our wide selection of AR-15 parts, AR-15 uppers, and AR-15 rifles, and leave a comment below. We would like to express a big thank you to David Lane for his diligent work on this article.