How to Build an AR15

How to Build an AR15 Lower

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Building your AR15 is a rewarding experience and it allows you to configure your rifle exactly how you want it. Building your rifle from scratch is usually less costly and helps you avoid having to deal with any unwanted parts you might be left with when upgrading an existing rifle. Cheaper Than Dirt! wants to help you create your custom assault rifle by not only providing you with the tools, but also the knowledge you need to build your perfect AR15.

Step 1

The first step in the building process is to purchase a stripped lower receiver. The lower receiver is considered a firearm unlike the rest of the AR15 parts you will need. If you want to know more about how to buy a firearm online you can refer to our easy-to-follow guide.

Lower Receiver

Select a Lower Receiver Group to view images.

LOWER RECEIVER GROUP

Lower Receiver
Lower Parts Kit
Receiver Extension
Action Spring
Buffer Assembly
Receiver Extension Nut
Locking Plate

Step 2

Step No. 2 is to buy all the parts you need to assemble the rifle. Complete rifle kits with a prebuilt upper will include everything you need to complete a functioning rifle (minus the stripped lower receiver). You can also buy the parts à la carte if you would like a more customized rifle.

Select a Upper Receiver Group to view images.

UPPER RECEIVER GROUP

Upper Receiver
Bolt Carrier Group
Charging Handle
Dust Cover Assembly
Forward Assist Assembly
Barrel
Pistol, Carbin, Mid-Length or Rifle
      Length Gas Tube
Gas Block

Optional Parts

Select a Optional Part to view images.

OPTIONAL PARTS

Upper Receiver Group

Delta Ring Assembly
Handguards
Handguard Cap
Free Float Handguard
Front Sight Post
Muzzle Device

Lower Receiver Group

AntiRotation Trigger Pins

Building the Lower Receiver

When you have all of your parts ready to install on your stripped lower receiver, make sure you have a clean and clear workspace.

Installing the Lower Receiver

Select Installing Lower Receiver Instruction for:

YouTube Video Instructions
1.) Place tape around the magazine catch slot to protect the finish.
2.) Insert the magazine catch into the slot on the left side of the receiver, and then insert the magazine catch spring over the threaded stud that appears in the hole on the right side of the receiver.
3.) Once you have both those parts in place, you can start by threading the magazine release button two turns onto the threaded stud with the smooth side facing the receiver.
4.) When the button is threaded onto the stud, depress the magazine button with a large punch as far as it will go below the surface of the receiver and tighten the magazine catch until the threaded stud is flush with the button.
5.) Line the magazine catch up with the slot in the receiver and release the pressure on the button.
6.) Insert a magazine, and then depress the magazine release button to make sure your magazine drops free from the magazine well.

You have completed your lower receiver! If you have purchased a preassembled upper receiver you can now pin that to your lower receiver with the pivot and takedown pins. Once the upper and lower receiver aremated together you are ready to go to the range and sight in your new AR15.

AR15 Tools