Real time inventory.  No backorders.

Lower Assemby

Lower Assemby

Finish your AR build like a pro, grab a ready-to-build lower assembly.

The hardest part of finishing any custom AR-15 build is putting together the lower receiver with the right parts. We've made it easy by pairing up our billet, forged, and polymer 80% lowers with all the other parts required to finish fabricating and assembling your new black rifle or pistol! We put together AR lower assemblies for all the most popular calibers with quality, mil-spec components.

Multi-Cal Lower Assemblies Available

Part of the benefit of investing in an AR-type lower assembly is the ability to easily convert between calibers. Grab any mil-spec 5.56/.223 lower kit on this page, and it'll be guaranteed to work with 300 BLK and 6.5 Grendel upper receiver assemblies, too. Ready to build a big rifle? Grab any LR-308 assembly and finish up a .308 Winchester, 7.62 NATO, or 6.5 Creedmoor build with ease.

Compatible With Existing AR Kits

Part of the benefit of buying an AR lower assembly is the easy reconfiguration to another caliber by simply swapping upper receivers. That's why all lower assemblies we sell are guaranteed to be compatible with the upper assemblies found in any of our existing AR kits (rifle or pistol) and existing AR parts you may have used (or want to use) for your existing build.

Not a Firearm (in most states)

Most states do not consider these lower assemblies to be firearms. That's because the included 80% lower is not fabricated nor functional as a firearm in its current state: It cannot take a trigger assembly or chamber rounds in the upper. You must fabricate your lower assembly, which is easy enough thanks to our available 80% jigs and super simple instructions.

Before ordering, please confirm that we can legally fulfill your order and ship to your residence in your state. We cover restricted states in our Shipping & Returns Policy. We cannot complete orders submitted from restricted states and must cancel such orders while issuing a re-stocking fee. We cannot make exceptions for active-duty military personnel or law enforcement. We appreciate your understanding.

We are a national retailer of individual components and not all products depicted on this website are legal in every state. Shipping of various products found on this website are prohibited to some states (such as California, Connecticut, District of Columbia, Hawaii, New Jersey, New York, Rhode Island, and Washington). The information, pictures, text or products presented on this website are not a representation by us, and should not be understood by you, that any product or completed firearm is legal to assemble or own in your state of residence. We encourage each and every builder to perform their own research about the state and federal laws that apply to them. It is your responsibility to understand the law and we encourage you to consult with an attorney or your local ATF representative.