Ultimate Guide for Building an AR-15 Rifle With an 80% Lower Receiver

The AR-15 is one of the world’s most recognizable and versatile rifles. Thanks to its simplicity, durability, and versatility, the AR has become one of the most popular rifles among gun owners looking to build an affordable yet effective firearm. Here’s what you need to know if you decide to build an AR-15.

What’s Needed to Build an AR-15?

For a basic AR-15, you’ll need the following parts to build a stripped lower receiver: 

Rifle receiver: The receiver is the part of the AR-15 rifle where the bolt and trigger are housed. You’ll also find the safety selector and magazine well on AR-15 receivers. Visit to learn more about AR-15 80 lower receivers. 

Bolt Carrier: The carrier is where the bolt securely rides on an AR-15 rifle. 

Buffer Assembly: The buffer is where the buffer spring is installed, which pushes the bolt carrier back when the gun fires a round. 

Buffer Tube: The buffer tube is where you’ll attach a stock to your lower receiver. 

Buffer and Buffer Spring: The buffer and spring are the parts that make the AR-15 rifle shoot harder and more accurately.

Local Laws

Some states allow you to own an 80% lower without a license since it’s not classified as a weapon. Adding a trigger and firing pin will convert the lower into a working firearm and require a license. Therefore, consult your local laws before purchasing and building a rifle from 80% lowers. 

Choosing a Caliber

There are two categories of AR-15s: gas-operated and piston-operated. Typically, gas-operated models use a short-stroke gas system and a rotating bolt to cycle the action. 

Piston-operated models use a direct impingement gas system in which the carrier pushes a bolt back with each round. You can choose a barrel according to your usage and preferences. 

The Most Important Part of Your Build

The most important part of your build is selecting an experienced and licensed gunsmith to work on your firearm. Never attempt to build or modify a firearm without the help of an SES (State-approved Firearms Instructor). Many deadly mistakes can be made when building your firearm. Some of the common mistakes include: 

– Failing to strip the firearm before any modifications. 

– Failing to inspect the firearm for wear and tear. 

– Failing to clean the firearm. 

– Failing to use the correct ammunition. 

Finishing Touches

One last thing worth mentioning is finishing touches. Applying a matte black finish to your lower receiver is highly recommended. You can also install a folding or fixed stock on your lower receiver. You can use a grip on the handguard to make handling your firearm easier. These finishing touches will give your lower receiver a custom look and make your AR-15 more comfortable to shoot.

Follow the above guide to building a custom-made AR-15 from an 80% lower receiver. Be sure to use proper tools to avoid damages to you or your property when testing the firearm. 

Leave a Reply

Your email address will not be published. Required fields are marked *