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The AR15 Rifle is one of the most versatile and user friendly rifles on the market. It is extremely user friendly in that with just a little patience you can learn the AR enough to be able to do all the cleaning an maintenance and even repairs and replacements with minimal tools. The AR platform is also the most customizable platforms out there. The nice thing is because of the plethora of aftermarket add on parts and upgrades, much of the customization can be done by the end user. Without the high cost of a gunsmith. Building an AR15 or other AR platform weapon is really quite simple, whether you want to build one from scratch or just upgrade or customize your AR. However what you will need is thorough knowledge of the parts of an AR15.

When getting to know your AR, the first thing is to understand that there are 2 parts groups that make up the AR, with a third being accessories. The 2 primary parts groups are 1. The upper and 2. The lower. The AR has an upper and lower receiver held together with two pins.

The above picture shows the Upper and the Lower receiver. It also shows a magazine and in the center the Bolt Carrier Group that fits in the Upper. The Upper and Lower are separated by removing the two pins. The nice thing is much of the maintenance to the AR Rifle can be done simply by removing the Rear pin and swinging the action open.

With the AR broken open and the front pin still in place you can remove the Bolt Carrier Group (BCG) you can easily do most cleaning and maintenance without completely separating the Upper and Lower. Lets watch a little video on the parts of an AR.

An upper receiver group consists of the following components:

  • Upper receiver – The upper receiver is the part that contains the bolt carrier group, and charging handle. The barrel and the for end are also attached to the upper receiver. Here is a picture of the Upper Receiver and barrel assembly.

  • Barrel - When it comes to ensuring the best possible shooting experience, especially when doing a precision shoot, the barrel of your rifle might be the most important part of your upper receiver. After all, your barrel will play a huge role in your accuracy on the range or in the field. Barrels come in a variety of lengths and weights based on your needs. Generally, a longer barrel will give you more accuracy, and a shorter barrel will provide you with more movability. For example, if you are building a long-range rifle for hunting or precision shooting, you might want a longer barrel length. If you are building a weapon that is designed to operate in a close quarter environment, such as home defense, you might want to get a shorter barrel length It’s important to keep in mind that, in most cases, your barrel should be at least 16 inches long. If it’s shorter than that, your weapon becomes a short-barreled rifle, which is against the law unless you have the proper paperwork and federal tax stamp. But there are a couple of ways to have a barrel shorter than 16 inches on your AR-15 without any paperwork. One popular choice is to build an AR pistol, or you could pin and weld a muzzle device on a 14.5” barrel permanently that is long enough to make the overall barrel length 16 inches.

  • Gas block and gas tube - Your rifle relies on gas pressure to operate in the way that it’s designed. After you fire your AR-15, gas pressure forces the bolt carrier group into the buffer tube, a process that facilitates the ejection of a used round and the chambering of a new one. After you fire your rifle, gas moves behind the bullet that’s leaving the barrel and moves through the gas port. It then goes inside the gas block, down the gas tube, and exits through the bolt carrier’s gas key. There are four different types of gas lengths: rifle-length, mid-length, carbine-length, and pistol-length. These different gas lengths are named after the location of the gas port on your barrel. Generally, your barrel length can be determined by reading the packaging or description. For the most part, gas blocks are installed on the barrel inside the handguard. The gas tube connects to the block and the upper receiver.

  • Bolt carrier group - There are a number of components inside the bolt carrier group, including the firing pin, bolt, cam pin, extractor, and gas key. At a very basic level, the bolt carrier group is responsible for loading your rifle, making sure bullets are fired correctly and ejecting spent rounds from the chamber. You can either buy a bolt carrier group that has been preassembled, or you can choose the parts you want individually and put it together yourself. The Bolt Carrier Assembly fits into the rear end of the Upper Receiver.

  • Charging handle - A charging handle is the part that pulls your bolt carrier group to the rear when you need to chamber a round or to clear a malfunction. If a round doesn’t fire as it should, you can simply pull on the charging handle to release the faulty shell and reload a new one. A charging handle also lets you load the first round of a new magazine if the bolt is closed. When you fire your AR-15, the charging handle remains stationary. The Charging handle sits above the Bolt Carrier Group and is what is used to chamber around and cock the hammer.

  • Forward assist - To enhance the AR-15’s reliability, the forward assist was added to the upper receiver. If for whatever reason your bolt isn’t operating properly and won’t close all the way, the forward assist should help make sure it goes back into battery. But not all riflemen find forward assists completely necessary. Some believe the component doesn’t offer that much additional functionality, while others view it as unnecessary cosmetic preference. On the other hand, there are plenty of gun owners who enjoy its dependability. The forward assist is used to make surethe bolt is fully seated.

  • Rail system or handguard - With all of the firing you do on the range, the barrel of your rifle can get hot very quickly. One of the primary uses of rail systems and handguards is to protect your hand from this heat so you can enjoy a comfortable shooting experience. Rail systems and handguards are the places that allow for AR-15 parts and accessories such as lasers, flashlights, optics, grips, sights, and bi-pods. This means you can customize your rifle accordingly. Like any other AR-15 component, rail systems and handguards come in all shapes and sizes. It’s important to keep in mind that the length of the equipment’s fore end is directly related to the length of the gas system you choose for your barrel: pistol length, carbine length, mid-length, or rifle length. There are a variety of Rail and handguard systems for the AR Platform

  • Ejection port cover - To make sure that your weapon functions as flawlessly as possible, you need to keep your AR-15 impeccably clean. That’s exactly where an ejection port cover comes into the equation. When it’s closed, the ejection port cover will prevent dirt, dust, and other debris from dirtying your rifle, as it keeps both the bolt carrier group and the upper receiver clean. The component only has one function – to be open or closed – but it’s an important one. You’ll have to close the ejection port cover on your own, but it will also open up on its own when the bolt carrier group moves to the back. The ejection port cover is a dust and debris cover for the ejection port to help keep it unobstructed. They can be found plain or with custom designs on them

The Lower Receiver Group The lower receiver group connects to the upper receiver group, and together, the two parts complete your rifle. You’ll find the trigger group, buffer tube, magazine release, safety selector, bolt catch, and other necessary components. You can either buy completed lower receiver groups or buy them stripped, assembling them on your own.

There are many different individual components that make up your lower receiver, including:

  • Lower receiver - The lower receiver is the part of your rifle that is generally considered to be the firearm itself (rather than just a component). For this reason, it is one of the most legally regulated parts of an AR-15. On AR-15s, the lower receiver is where you’ll find your weapon’s serial number. The picture below shows the lower assembly including the Lower housing, Trigger group, pistol Grip and stock.

  • Trigger group - You can’t fire your rifle at all without a trigger. And you can’t fire it accurately if you don’t have a trigger pull weight that feels comfortable to you. The trigger group consists of the trigger and the hammer of your AR-15, as well as other necessary housing components. Like any other piece of your weapon, you can customize the trigger of your rifle to your exact specifications. Triggers can also play a pivotal role in your shooting experience. You’ll enjoy more accuracy and faster a firing rate when you’re using a lighter trigger. But keep in mind that a light trigger might easily lead to negligent discharge (ND) due to the ease of firing. That is the reason why Military and Law Enforcement uses heavier triggers on their duty weapons for liability reasons. Everyone has their own opinion on what constitutes a ‘light’ trigger, and our rule of thumb is that any trigger lighter than 4.5 lb is considered light. The United State Military is using 5.5 to 8.5 lb triggers on their standard-issue M4s.

  • Lower parts kit - Many gun enthusiasts enjoy putting their rifles together themselves. After all, the better you know the anatomy of your AR-15, the easier it will be for you to customize it to your exact specifications and to identify the cause of malfunctions. While you can certainly buy a completed lower receiver group, you can also buy a stripped one and put it together yourself with a lower parts kit. What’s better than shooting with precision than with a weapon you assembled yourself? Buffer tube / buffer - As part of your rifle’s recoil system, the buffer helps absorb a lot of that kick, making your shooting experience more seamless. The right buffer can give you an edge over your competitors, as you’ll be able to shoot accurately for a longer period of time. Buffer tubes house both the buffer and the buffer spring. Together, these components slow down the faster parts of your rifle’s action, protecting both themselves and the frame. This ensures that the integrity of your weapon remains intact. With a pistol buffer tube, you’re able to build a shorter barrel weapon without having to obtain the usual paperwork because the A.R. will classify as a pistol. This allows you to use any length of barrel on your weapon – even those that are shorter than 16 inches. The picture below is of the Buffer, Buffer Tube and Buffer Spring.

  • Butt stock - How your rifle rests on your shoulder plays a major role in your overall gunning experience. It’s easy to be distracted if you’re uncomfortable while aiming at targets. In the simplest terms, the stock is the part of your AR-15 that connects to the rifle’s firing mechanisms. Like most other parts of your gun, you can choose among a wide array of stock options to build your rifle to your exact specifications. As you begin your search for the stock that’s right for you, the component will fall under two categories: fixed stock or collapsible/adjustable stock. While collapsible stocks help you place the perfect amount of distance between your shoulder and your rifle, fixed stocks are more formidable and can help counter heavier front ends. The Butt Stock, comes in a variety of styles. The two primary classifications are Fixed and Collapsible/Adjustable. Some Jurisdictions do not allow adjustable stocks.

  • Magazines - You need to hold your bullets somehow, right? That’s what magazines are for. You can get different sized magazines, but it’s important to keep in mind that laws for the size of magazines can vary from state to state. On top of that, because of the political climate, you never know when these kinds of laws might change. It’s important to stay in the loop about these rules, so you can make sure you’re within the confines of the law.

Magazines are available in a variety of capacities. Check your Locality to see what is legal where you are.


To ensure the best shooting experience, you have to have the firmest grip on your rifle. When it comes to getting the best hold on your rifle – and therefore the most accurate shots – you’ll have to consider both of the following:

  • Pistol Grips - Your trigger hand has the final say as to when a bullet is fired. That’s why you need to make sure that your trigger hand has the best possible grip on your AR-15 as possible. The pistol grip attaches to the lower receiver, giving you a firm handle of your rifle. You can choose among a multitude of grips, finding the accessory that feels best in your hands. The better your grip, the bigger your advantage. The first picture is California compliant Stock and Grip

Stanard AR Pistol Grip. Check to see what is legal where you are.

  • Fore grips - Both of your hands play a crucial role in determining how accurately you fire your rifle. In addition to getting a good pistol grip with your trigger hand, you might also need a strong fore grip to ensure that you’re shooting a steady gun. Fore grips can be installed vertically or angled, depending on your preference. Choose whichever grip is most comfortable for your own shooting style to fire most accurately, and you’ll naturally give yourself an edge against your competitors. Picture of a variety of fore Grips. Some jurisdictions do not allow fore Grips.

That gives you a pretty good breakdown of the AR15. It really is not a scary firearm when you get to know it. Many people call it a high powered rifle. However the round it fires is much smaller then many hunting calibers. That completes this installment. We will have more great information on the mystery of the AR Platform Rifle to help you get to know it. Please like and comment.

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