If you’re an AR-15 enthusiast you’ll likely want to build your own AR-15 at some point. There are a few ways to go about doing that but one of the most popular methods is building from an 80% lower. What’s an 80 lower build? Well, if you don’t know what an 80 lower is, it’s the lower receiver of an AR-15 that is only 80% done. The trigger group and safety selector area are not milled out and must be finished by you in order to be considered a firearm. This means a couple things – the firearm is not registered or tracked by the ATF and no FFL is required. If you want an “off the grid” AR-15 that the government doesn’t know about, this is the only way you can currently do it.
Building an AR-15 from an 80% lower receiver is incredibly satisfying and can provide hours of enjoyment. Unfortunately, though, some builders buy the lower but don’t buy or have access to the tools needed to finish the lower. This leaves them with trying to mill with incorrect tools and ultimately a sub-par build. If you don’t want to fall into that category of builders, read on.
Tools For An 80% Lower Receiver Build
As with a lot of projects, having the right tools readily available can make the difference between a great finished lower and a just okay lower. Don’t get caught at the range with an AR-15 that you built that leads to a laughing session with all your buddies.
#3 Tool: A Vice
There are a lot of tools that come close to being the third must-have tool for finishing an 80 lower. However, after a number of 80 lower builds and learning from experience, a vice is an absolute must. You would think it would be common sense but that’s simply not the case. Having a good vice makes a huge difference. Having a good dual axis vice is even better especially if you are using a drill press instead of a hand drill to do the milling. A vice that is securely fastened to a bench or drill press is a must.
#2 Tool: 80% Lower Jig Tooling
Having a good vice makes no difference if you don’t have the right jig tooling. This means having the correct bits for drilling as well as milling. A typical 80 jig tool kit set includes an end mill bit, 3/8″, 5/16″, and 5/32″ drill bit as well as a 3/8″ drill stop. It’s important to remember that even though you might be able to find an end mill bit at the local hardware store, you shouldn’t use it. Hardware store end mills aren’t specifically made for 80% lower jigs and, as such, you risk damaging your jig. Make sure to use the right tooling for the job.
#1 Tool: 80% Lower Jig
I know, I know…you may be thinking that a jig isn’t a tool. Oh, but it is…an absolute must-have if you do any type of milling on an 80% lower. For those unfamiliar, a jig is acts as a guide for the tooling you’ll be using. If you don’t have it then you are almost guaranteed to royally screw up your lower. By all means, if that’s your goal then don’t use a jig. For everyone else, add an 80 lower jig to your tool box. There are plenty out available and they all perform the same or similar functions. A good jig is usually well labeled, includes instructions, reinforced in certain areas for use, and can be used on multiple builds.
Well there you have it. These three tools are what we consider must-have tools for finishing an 80% lower. Are there other tools needed? Yes, of course, but none we find are important as these. Other tools you’ll want to have are a drill press or hand drill, vacuum, oil, various screwdrivers, and Allen wrenches, to name a few. Feel free to let us know what tools you use to finish your 80% lower – we’d love to see the different setups out there.