How To Build an Unregistered AR-15 - Legally

Apr 16th 2018

At AR-15 Lower Receivers, we refuse to buy into the media's scare tactics, which are nothing more than an attempt to cast doubt on the legitimacy of the Second Amendment. Especially, when it comes to the AR-15. A pistol grip, detachable mag and the color black do not make a firearm inherently evil.

While many spend their time demonizing weapons, we help create the means by which innocent civilians can exercise their constitutional right and protect themselves. We live every day standing for the core values that made America great and we'll do whatever necessary to protect this great country of ours and help others do the same.

Some doubt the threat of disarmament within our own borders. Others are getting prepared just in case. And if you're wondering why the 80% lower receiver is becoming more popular - now you know.

Building An Unregistered AR-15

The viscera of an unregistered AR-15 is its 80% lower receiver. Here's why!

According to the Bureau of Alcohol, Tobacco, Firearms and Explosives (BATFE) the only part of the AR-15 recognized as a firearm is a lower receiver, which has been completed and serialized by the manufacture. This refers to a serialized lower receiver sold as completed and not requiring any additional milling or drilling by the purchaser. A serialized lower also requires a Federal Firearms License (FFL) transfer at the time of purchase.

The only exception applies to the sale of 80% lower receivers. The BATFE does not recognize 80% lower receivers as a firearm and, therefore, they can be sold without serialization or an FFL transfer.

An '80% lower' refers to a lower receiver sold as incomplete and inoperable. The title, "80% lower" is given due to the fire control group cavity remaining unmilled and in its original state. Hence, 80% lowers do not meet the BATFE's legal definition of a firearm.

In most states an 80% lower receiver is legal for both purchase and possession. They can also legally be milled, drilled and made operable by the purchaser. The purchaser must complete the milling of the fire control group, finish the 80% lower for his or her own personal use, and cannot not sell the lower receiver after manufacturing.

The BATFE states: Individuals manufacturing sporting-type firearms for their own use need not hold Federal Firearms Licenses (FFLs). However, we suggest that the manufacturer at least identify the firearm with a serial number as a safeguard in the event that the firearm is lost or stolen. Also, the firearm should be identified as required in 27 CFR478.92 if it is sold or otherwise lawfully transferred in the future.

Building An Unregistered AR-15

While in the purchase process of your 80% lower receiver, consider purchasing an 80% lower jig. An 80% lower jig provides a convenient way to complete your 80% lower. It will also offer precision tolerances, which in turn means a well functioning and tight fitting lower. You may also consider purchasing an 80% jig pack if wanting to build more than one AR. These packages provide convenient one-stop-shopping for the aggressive AR builder.

While an 80% lower does not require a multitude of tools, you will need a drill press, drill bits and end mills. The overall process of completion is simple and your DIY skills will make it easy complete an 80% lower in no time.

Don't let the thought of finishing your AR's lower seem intimidating. Literally, there are thousands of people just like you who have finished their own 80% lowers without a single issue.

Unregistered AR-15 Facts

While the BATFE does not regulate the drilling and milling of an 80% lower receiver, there are a few facts you should be aware of.

  1. If you choose not to serialize the AR it cannot be traced if lost or stolen.
  2. If your home is ever searched by law enforcement, you may be questioned regarding the possession of such a firearm. While 100% legal, it is your responsibility to know the law and be able to defend your right of owning a non-serialized firearm.

To build an unregistered AR-15, check out our 80% lower jig packs, AR 15 Rifle Build Kits, and various other AR parts you'll need to complete your AR 15.

Have fun, be safe and support the Second Amendment!

(PLEASE NOTE: AR-15 Lower Receivers in no way sponsors the illegal manufacturing, sale, or possession of firearms. You are required to know and understand federal, state and local laws governing the ownership and completion of an 80% lower. Please verify your state requirements before purchasing an 80% lower receiver.)

DISCLAIMER: If you are new to the world of DIY gun building, you likely have a lot of questions and rightfully so. It’s an area that has a lot of questions that, without the correct answers, could have some serious implications. At, we are by no means providing this content on our website to serve as legal advice or legal counsel. We encourage each and every builder to perform their own research around their respective State laws as well as educating themselves on the Federal laws. When performing your own research, please be sure that you are getting your information from a reliable source.