This is Worth Firearm’s guide to 80% lower and stripped lowers. Be sure to check with state and federal laws prior to purchasing or completing a lower receiver – the AR 15 landscape is changing every date.

I expect the 80% lower to someday go away. With Biden in office, Dave Chipman potentially becoming ATF Director, and the potential craziness that seems to happen while Democrats are in office – this is a real possibility. - From IG @gunpolicy

What is an 80% Lower?

An 80% lower is an unserialized rifle lower receiver that is missing holes in it to assemble it as a functional rifle lower receiver. It’s essentially a block of metal.


To make the 80% lower function for use as an AR 15, you’ll need to drill some holes. For that, you’ll need a drill press.

Drawback – using the drill press in at your home will not be the same precise quality you’ll get with a manufacturer’s stripped lower.

But there’s at least one saving grace – many of the 80% lower manufacturers offer jigs that will help you navigate drilling the holes into the 80% lower receiver blank.


No of course this isn’t limited to just AR 15’s. These are also available for AR 10 platforms as well.

Is a Drill Press All I Need to Build an 80% Lower?

So you’ve followed the manufacturer’s directions closely and you’ve drilled your 80% lower. Congrats – you now have the equivalent to a stripped lower.

Now you’ll need a lower parts kit. You’d also need this with a stripped lower.

Ready to build firearm

You’ll also need a buffer tube, buttstock, buffer spring, castle nut, and buffer.

In our experience – most lower parts kits have a trigger assembly in it. You could purchase an upgraded trigger.

Considerations Around State and Federal Laws

We mentioned this before – the rules should be considered EVER CHANGING. Being based in Texas, we are able to purchase this part (without a background check of course) and “enhance” it to make it a stripped lower.

However, using this receiver blank might be subject to future changes to local and state laws, much less federal laws. Please be cautious in doing this.

What is a Stripped Lower?

A stripped lower is a serialized lower receiver rifle part that is ready for assembly as a rifle (i.e. – AR 15, AR 10). Since it’s serialized and identified as a rifle by the ATF, you’ll need background check (or an applicable gun licenser per your state’s laws).

Aero Builds a Superior Product

How Build an AR 15 or AR 10

DIY gun building is almost like legos for adults. I used to build computers in my spare time – it’s just as rewarding to complete a gun build. You’ll price out and buy all your parts.

I personally enjoy the process of making sure all the parts go together.

Building a pistol braced AR 15? Buy the proper individual components (for a pistol brace), the proper weight/strength buffer and buffer spring.

Read: Best AR-15 Stripped Lower

Look at our list above for a comprehensive list of parts – you won’t need the drill press. You’re welcome.

Carbine length AR 15? Buy the right parts for that.

Rifle length AR 15? Same goes here too.

There are commercial and mil spec sized buffer tubes – very important. I don’t recommend going commercial spec buffer tubes – frankly I don’t know why they exist. You’re setting yourself up for limiting your buttstock options – as most buttstock manufacturers are likely to favor production of products that are compatible with military arms.

Don’t think of it in terms of legal and illegal. The laws do not identify the 80% lower as illegal (yet). They’re both vehicles to firearm ownership.

But How Do I Assemble an 80% Lower or Stripped Lower?

My first AR 15 build was pretty difficult. It wasn’t an 80% lower. It was a stripped lower.

I bought the parts I thought I needed but still came up short in some areas.

Check out’s AR15 Lower Receiver Assembly Guide. You can also find videos on YouTube if you have any issues anywhere in the instructions.

Easy to Master

Once you’ve assembled your first AR 15 (whether from an 80% lower or stripped lower), you’ll find there’s really nothing to it.

Soon you’ll be so good you can create your own custom firearms (AR 15’s anyways – and AR 10’s aren’t really all that different). Be sure to conduct your own research and buy the proper parts. Buying parts without your own research could lead to wasted dollars or just future parts for your next build.

Even better – you’ll have a deep appreciation for the parts and how they function. You’ll also be able to problem solve any issues with your 80% lower or stripped lower build.

What about Local and State Laws with an 80% lower?

This is a tricky one. You’ll need to see what your state laws are. Many of the 80% lower websites will give you details about your state laws.

Where can I find an 80% lower?

A simple Google search is all you need to find an 80% lower. Unfortunately, Worth Firearms does not carry 80% lower receivers.

Companies like James Madison Tactical sells 80% lowers in both AR-15 and AR-10 configurations.

You can also find some great 80% lowers at 80% Arms.

Build an AR 15 with Worth Firearms

We do however carry stripped lowers. Even better though, is that we carry Aero Precision Builder Sets. These builder sets include the stripped lower receiver, stripped upper receiver, and matching free floating handguards. We also carry other manufacturer’s build kits.

Where to Find Your Parts

You’ll need to purchase the other parts: upper and lower parts kits, parts for the buttstock (buffer, buffer tube, etc), bolt, charging handle, gas tube, barrel, muzzle device, etc. will have a complete list of parts for your AR15 build.

Worth Firearms carries all these parts! We have excellent customer service and can help consult with you on your AR 15 needs.

Gunsmithing Services

Not sure if you’re able to build AR 15? Feel like you’d rather have a professional do it? Have an gunsmith do it!

Worth Firearms will connect you with a qualified gunsmith to assemble and even test your AR 15. Ask about these services when you purchase your parts!

This article is not intended as legal advice. You can contact your local ATF representative if you have questions. My local ATF representative was familiar with Texas related gun laws as well – which helped me in my FFL process.

Building a firearm without knowing current laws leave you in a bad position with serious implications. Be sure to read up on barrel lengths, pistol braces vs buttstocks, and other rules and regulations around 80% lower receiver builds.

Do not assemble your firearm parts unless you’re sure you’re in accordance respective state laws – as certain states have rules beyond the federal ones.

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