Over the last couple of articles about lower receivers, we have established that the completed lower receiver is the firearm. There are a few steps involved when purchasing a completed lower receiver, including background checks, picking the receiver up from an FFL, and paying a fee. In this article, we are going to talk about 80% lowers, the differences between 80% lowers and stripped or complete lowers, and the benefits of purchasing an 80% lower.  

80 PERCENT LOWERS DEFINED



Anderson AR-15 80% Lower Receiver - Black Anodized - No FFL Required

80 Percent Lower is not a statutory term that is recognized by ATF, it is more of a term used by AR-15 builders and firearms enthusiasts when they are describing an unfinished receiver. As you can infer by the term, 80% of the lower receiver has been completed, but the remaining 20%, which is the most important part, is left to be completed by the purchaser. AR builders often refer to them as blanks, bricks, or even paperweights.

ARE THEY LEGAL

An 80% Lower is simply a term used to describe an unfinished receiver that has not yet reached the stage of manufacturing that meets the definition of a firearm, frame, or receiver. Unlike stripped or completed receivers, 80% lowers are not considered firearms and therefore are not governed by the ATF. That means that there is no background check and no need to involve an FFL. A purchase of an 80% lower can be delivered right to your front door. Since they are not firearms in the 80% completed state that they arrive in, there is also no need to serialize them, register them, or go through any of the red tape that usually accompanies the purchase of a firearm. As defined by ATF: 80% receiver, " "80% finished, "80% complete, "unfinished receiver " are all terms referring to an item that some may believe has not yet reached a stage of manufacture that meets the definition of firearm frame or receiver found in the Gun Control Act of 1968 (GCA). These are not statutory terms or terms ATF employs or endorses." - Bureau of Alcohol, Tobacco, Firearms, and Explosives (BATFe). Some state and local laws may vary. Check the laws of the state that you live in before buying or building a firearm.

AR-15 80% Lower Receiver - No FFL Required

WHAT ARE THE DIFFERENCES

  The differences between a completed receiver, a stripped receiver, and an 80% lower are many.
  • COMPLETED LOWERS - A short definition is that a completed lower receiver contains the operating parts of the firing mechanism. If you purchase a completed lower for your build, it has been prebuilt with a lower parts kit and buffer assembly already installed. There is one very important thing to understand when purchasing a completed lower for your AR build. The completed lower IS a firearm. The lower receiver is the only part of an AR that is considered to be a firearm. It is the part of the frame that has been serialized. Since the completed lower receiver is considered an actual firearm, it is regulated by both state and federal laws. When purchasing a completed lower, the customer must go through all of the paperwork, background checks, and FFLs, just like you would when purchasing a firearm. (cc)
  • STRIPPED LOWERS - Stripped lowers are no different than completed lowers in one sense. Stripped lowers are also firearms and are considered to be 100% lower receivers. Since stripped lowers are also considered firearms, they are subject to all of the paperwork, background checks, and FFLs as the completed lowers. A stripped lower does not contain a lower parts kit though. Without a lower parts kit, you have the freedom to pick and choose each and every component that goes inside of the lower receiver to make it functional. (cc)


FMK AR1 Extreme Multi-Caliber, Mil-Spec, AR15 Lower Receiver

HOW TO COMPLETE AN 80 PERCENT LOWER

  As received, an 80% lower will not accept a parts kit or trigger kit. Those components can only be accepted in the receiver after some tooling and machining. Making an 80% Lower into a completed receiver is not complicated but it does require some work to be completed by the purchaser. An 80% lower becomes a completed lower receiver by milling out the fire control pocket. This is a simple process using tools that you likely already have. Some recommended tools to have on hand when starting the transformation of an 80% lower to a completed lower are an 80% lower jig, 3/8" End Mill, 5/16" Drill Bit, 3/8" Drill Bit, 5/32" Drill Bit, a Dremel with a 1/4" grinding head, a Drill Press, and Drill Press Vice. Don't be in a hurry to make your 80%er into a completed receiver though. Take your time and get it right the first time. There are video and written tutorials all over the internet, just make sure that your source for instructions is a legitimate and trusted member of the firearms community. Don't get your instructions from someone using big words or complicated techniques just to stroke their ego. This could confuse you or complicate the process. It truly isn't that hard, find instructions that make sense to you and that you can understand. Diagrams can be really helpful here.

Spikes Tactical Crusader Stripped Lower

80% LOWER SELECTIONS

  Forged blanks are the most popular purchase among those looking to start an AR build. They are tough and reliable, and most importantly they are affordable. Billets are another popular choice among AR builders, they are easy to machine. Polymer blanks are also easy to machine and offer a great alternative to other blanks because of its light weight. Cast blanks are created by pouring alloys into a mold. Be wary of these blanks, as the pouring process can create air bubbles and other imperfections that could alter the integrity of the blank to be used in an AR build, and could lead to a catastrophic failure.

Polymer-80 80% AR-15 Lower

WHAT ARE THE ADVANTAGES

  In addition to all of the advantages of skipping the red tape of the purchase of a firearm, there are two main reasons why AR builders choose an 80% lower. The main reason is cost. The 80% lowers are relatively inexpensive considering their important function to a completed firearm. Overall, purchasing one will be one of the least expensive components in your build. The second most important reason why an AR builder would want an 80% lower is the raw challenge. This is where the rubber meets the road and is the down and dirty of creating a firearm from the ground up. In selecting an 80% lower for your build, you will have a unique opportunity to know your firearm inside and out when your build is complete. Knowing the functionality of your firearm allows you to quickly diagnose potential problems and easily replace a part or component. There are so many different component pieces on the market right now, your selections for your AR build will truly make it a one of a kind.  

Polymer 80 Zombie Green AR-15 Lower

 

BRINING IT IN FOR A LANDING

There are many reasons and advantages for purchasing an 80% lower. Three come to mind right away, the cost, the challenge, and the bragging rights. The lower receiver is an important part of a build, it must be reliable. Building an AR allows you to choose your components, therefore personally playing into the functionality and reliability of your firearm. There is a lot of pride and a sense of accomplishment in building an AR, especially when you build it from the ground up with an 80% blank. Shop All Lower Receivers
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