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What is an 80% Lower Receiver

You may have heard about 80% Lowers among your AR builder buddies and still have questions about the 80% lower receiver build market including the legality of 80% lower receivers, the rules and how to use an 80% lower jig, what tools are needed to build an 80% lower firearm, and what type of 80% lower should I buy?

There are many decisions when selecting your 80% lower including; Billet 80% Lower vs Forged 80% Lower, 7075 vs 6065 Lower Aluminum material, Raw vs Ano 80% Lower, Cerakote vs anodized, etc. 

Don't worry we at are here to help you with your selection of the right 80% lower and help you start building your AR rifle today.


Use this guide to help understand the 80% Lower firearms market

  • What is an 80% Lower Receiver
  • Legalities of owning an 80% Lower Receiver
  • Do I need a FFL to make a 80% Firearm
  • What tools do i need to complete an 80% Lower AR Build
  • Valuable resources for 80% Builds
  • Overview of a AR15 and AR10 80% Lower Receiver
  • Coating and Engraving Options


What is an 80% Lower Receiver?

The Lower Receiver is the Part of the Firearm that requires serialization and in some states registration of your firearm. This is a way to track the firearm itself. The Lower receiver is the part of a firearm that houses the operating parts including the trigger group, safety selector, buffer tube assembly and magazine port. Under the United States law the receiver is the actual firearm itself and is the controlled part without which operation is impossible. The law views the receiver as that part of a firearm housing that has the serial number upon it. In the case of a firearm that has multiple receivers such as the AR-15, which has an upper and lower receiver, the legally controlled part is the one that is serialized (the lower, in the AR-15's case).

An 80% Lower Receiver is the foundation for any AR build. An 80% lower receiver is a product that allows a gun enthusiast and firearm builder to complete their own custom AR-15 or AR-10 Rifle without any paperwork and with no FFL transfer. By definition of the law, an 80% lower is not considered a firearm since it is not functional in its current state and not until its 100% completed and functional is it deemed a firearm. By design, the 80% Lower receiver will still require the 80% Builder to complete the remaining 20% of milling to complete the firearm. 80% Lower jigs are tooling clamps that make it easy for the 80% Lower builder to mill precise and accurate finishing of the 80% lower to see it to 100% Lower completion. 

An 80% Lower is a partially completed piece of material such as aluminum that requires custom machining work to be completed an considered a firearm by US Law and ATF standards. 

Legalities of owning an 80% Lower Receiver

Many of our beginner 80% Lower builders have questions as to how our 80% AR-10 and AR-15 Lower Receivers are considered to NOT be a firearm.  We have received a determination letter from the ATF stating that the ATF does not view this as a firearm because to complete the receiver it requires specialized skills and tooling. Customers who wish to build an 80% firearm are NOT required to register the firearm since there is no serialization required (Although recommended) Our 80% lowers and all remaining AR parts can be simply ordered online, shipped directly to your door with complete privacy and zero government oversight and involvement.  

Do I need a FFL to make a 80% Firearm?

No. You do not need an FFL to make an 80% firearm or 80% Lower. You do however, still have to adhere to your federal and state laws in owning a firearm. For example in non gun-friendly states such as California you must adhere to California DOJ laws and make sure you have a California Compliant firearm such as building it with a Bullet Button, a 16" or larger barrel for rifles, and 10 round magazines or less. 

As long as you can legally own the firearm in the state, county and city you reside in you are allowed to manufacture a firearm for your own personal use. There is no serial number required for your 80% Lower, however, it is suggested to engrave a serial number, model and manufacturer on your receiver in case it is lost or stolen. 

All National Firearms Act (NFA) regulations apply to your firearm. You may create a short-barreled rifle out of your firearm via a BATFE (Bureau of Alcohol Tobacco Firearms and Explosive) Form 1 after BATFE approval.

What tools do i need to complete an 80% Lower AR Build

The most common methods in completing an 80% Lower receiver are to use a manual mill or a drill press. Manual Mills and Drill Presses can be purchased from local tool suppliers such a Harbor Freight, Home Depot, Lowes or online websites such as eBay or amazon. 

Once you identify what machine you have or will use then its recommended to purchase an 80% Lower Jig that works with your 80% Lower Receiver. The 80% Lower Jig will house the 80% Lower Receiver of your choice and will have all components aligned for easy milling and drilling to complete your 80% Lower Receiver. Our 80% Lower Jigs are built from high quality materials and you will be able to reuse the jig to make multiple 80% Lowers. 

Valuable resources for 80% Builds

You can discover a myriad of 80% Lower articles, forums, and blog resources on the internet to get help and information from the home AR builder and home gunsmith community.

Some of our recommended forums are the following: & Home Gunsmith - The Weapons guild and home gun smith are two great communities of home builders who would be more than happy to help you in your 80% completion project.

Overview of a AR15 and AR10 80% Lower Receiver


The 80% AR-15 Lower Receiver is our most popular 80% lower receiver and works with .223, 5.56, and 300 Blackout ammo. 

There is a tremendous amount of parts available in the commercial market which allows for an unlimited number of combinations and custom AR15 configurations for any gun enthusiast. Our AR15 80% Lowers are machined to Mil-Spec and any military specification commercial AR-15 product  will work with our 80% AR-15 Lower Receiver.

The 80% AR-15 Lower Receiver is a great foundation for many caliber 80% rifle builds including: .223mm, 5.56mm,  7.62x39mm, 5.45x39mm, 6.5 Grendel, 6.8 SPC, .50 Beowulf, 9mm, .45 ACP.


Our AR-10 Lower Receiver is our .308 / 7.62 AR-10 Variant lower. Our AR10 80% Lower is a .308 80% lower receiver similar to the AR-15, AR-10 and LR-308 platforms. The .308 uses the same fire control group and operations required by the AR15. Our AR10 .308 lowers are patterned to DPMS Specifications and will work with DPMS patterned AR10 Parts. 

The AR10 lower receiver (.308) is compatible with DPMS upper receivers and DPMS .308 products. The stocks are the same for the .308 and the 5.56 as well as the custom pistol grips. 

Coating and Engraving Options

We offer our 80% Lower receivers currently in two versions; RAW and Anodized. Raw 80% Lowers will save you a few bucks and will allow you to completely customize your 80% Lower once you complete it. This gives the 80% gun builder the option to anodize or cerakote the lower yourself and to pick from a number of custom colors. if you want to purchase an 80% lower already finished we also sell our 80% Ano Lowers that we finish with a very high-end Type III Hard Anodize process that provides a beautiful black finish. This option takes the work out of completion and takes care of that final step. Since the majority of gun builders prefer Black Anodized firearms we offer this edition on our 80% Lowers.