Jumping into the project of building your own AR-15? Then you’re likely doing a little research as you read this. If you searched enough, you’ve come across the terms “stripped lower receiver” and “80 lower.” So, what is a stripped lower receiver? In simple terms, the stripped lower receiver is the firearm itself, as defined by the ATF. Everything else – upper receiver, barrel, trigger, pistol grip, buttstock, and so on – are simply components. The 80 lower is a nearly-finished stripped lower receiver, and we’ll explain why it’s so amazing in just a second.
The AR-15 stripped lower receiver
Functionally, the AR-15 stripped lower receiver is the housing (available forged, billet, or polymer) that holds your lower parts kit, your buffer system (buttstock, tube, spring, and buffer) and your magazine. The AR-15 stripped lower receiver is the only component in your project that is considered a firearm and subject to actual firearms laws.
An 80 lower, or officially, an 80% lower receiver, is a nearly-complete receiver that still isn’t quite yet considered a firearm. That’s where you come in!
An 80 lower isn’t a stripped receiver (yet)
We are not lawyers, and you should always check your local gun laws to ensure your build is legal. However, we certainly set you on the right path:
When you purchase an AR-15 stripped lower receiver, you’re buying a firearm. You’re now required to submit paperwork, conduct a background check, pay a bunch of fees, and in some states, you have to wait a few days before you can even pick up your lower receiver.
But the 80 lower isn’t a firearm, so you don’t have to deal with all that! When you buy an 80 lower, you’re simply buying a piece of aluminum. The ATF doesn’t care, nor do any other agencies. But what do you do with it?
Turning an 80 lower into a stripped lower
Would you rather wait an hour while that background goes through? Or would you rather spend that hour by immediately building your AR-15?
Once you’ve received your 80 lower, all you need to do is complete it! By completing your 80 lower, you’ll turn it into a legal-by-definition AR-15 stripped lower receiver, a firearm! You can then use your 80 lower to complete your AR-15.
Completing an 80 lower takes little time
Completing your 80 lower with an 80% jig will take around one hour! Even if you’ve never machined metal, this project is super easy. The 80 lower was carefully designed so that amateur gunsmiths – like you – can confidently complete this project at home with some basic tools and an 80% jig. All you need is that jig. We recommend the 5D Tactical Router Jig PRO. It’s a customer favorite and it includes all the tooling you need.
What kind of tools do you need? Easy:
- 80% lower jig
- 5/32” Drill Bit
- 3/8” Drill Bit
- 5/16” Drill Bit
- 3/8” End Mill
- Handheld Router
- Hand Drill
- Drill Press Vise
Grab an 80% jig
All of our available 80 lower jigs include the necessary tooling. All you’ll need are the last three tools listed above (a router, drill, and vise). We even sell the most popular and most-recommended router for your convenience (the Porter Cable 6430), linked above! Each 80 lower jig includes the necessary instructions. Once you’ve completed 80 lower, all you need to do is install your lower parts kit and buffer system, and slap on the AR-15 upper of your choice!