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If you’re reading this, then you’re interested in building your first AR-15 from scratch – but you have no idea what an 80 lower is, or how the whole thing works. That’s okay! Today, we’re giving you an overview of finishing an 80 lower.

#1: What an 80 lower is

An 80 lower is a piece of aluminum alloy – either billet or forged – that mostly resembles an AR-15 stripped lower receiver. This piece of aluminum is not considered a firearm, and that’s where you come in. You, the builder, will machine your 80 lower to completion, transforming it into a legal-by-definition firearm, an AR-15 lower receiver.

This is arguably the most affordable way to build a custom AR-15, and rest assured it is 100% legal to do in all 50 states. Keep reading:

#2: The laws of the 80 lower

The Bureau of Alcohol, Tobacco, and Firearms states that an individual can legally build a firearm at home, no paperwork required. Your finished AR-15 lower receiver cannot be made with the intent to sell it – only you can use it.  Nonetheless, no paperwork, FFLs, transfers, or fees are required! Our 80 lower jigs and kits also ship straight to your front door with no paperwork, so you can get to building right away.

Some states require your finished 80 lower to have a serial number before you machine it. Check your state and local laws in further detail before building an 80 lower.

#3: The 80 lower tools you need

Machining and finishing an 80 lower is surprisingly simple. In lay terms, you’re only required to drill a few holes and mill out some aluminum from inside the 80 lower. These steps generally take less than two hours, and experienced builders can complete an 80 lower is as little as 30 minutes!

Here’s the official list of tools you’ll need to finish your 80 lower:

  •         *Drill Bits
  •         *End Mill Bit
  •         80% Lower Jig
  •         Drill or Drill Press
  •         Handheld Router
  •         Machine Oil/Lubricant
  •         Lower Parts Kit

*Included with 80% Lower Jig.

#4: Finish your 80 lower

The steps necessary to complete an 80 lower vary slightly from jig to jig, but the general process is all the same. We strongly recommend viewing the appropriate tutorial provided with the 80% jig you select, before you attempt to finish your 80 lower.

Finishing your 80 lower will involve setting your lower up in your jig, securing your jig, and setting your drill depths for your drill or press. Your 80% jig will include drill depth guides, removing any need for measurement – the same applies for your end mill bit.

#5: Finish your rifle or pistol

Once you’ve finished your 80 lower, take a step back and pat yourself on the back – you’ve just built your first firearm from scratch! Once complete, your AR-15 stripped lower receiver will be perfectly capable of accepting any standard lower parts kit equipped for your selected caliber.

Pick up one of our lower parts kits and a complete upper when you order your 80 lower and jig, and you’ll be ready to build in a single afternoon!

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 80Lower Jigs, 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.


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