Making your own AR-15 lower offers several advantages. Pride in accomplishment, control of product tolerances, and the ability to customize your firearm to your liking.
An 80% firearms receiver is not considered a firearm, and does not require an FFL to acquire. These incomplete receivers are designed to have the remaining 20% of the machine work done by the end-user without needing a full production shop or CNC machine.
Building your own receiver is made easy with a jig. There are many 80% lower jigs that can be found on the marketplace. These jigs guide your cutting tool of choice to hollow out the remaining 20% of the machining work that exists on an 80% receiver.
Often, the tools you’ll need access to include: Calipers, a drill press, a vise, and machining oil.
The first step is to ream out the trigger assembly region. This will require control of the depth of the cut, and guidance from the jig to cut it to the proper dimension.
The next step is to drill the holes for the trigger assembly pins, the safety, and the rear retaining pin.
Once these steps have been completed, you have a complete lower receiver, prepared to accept a lower parts kit, which will include your trigger assembly, assembly pins and the magazine catch and release. The result is a firearm of your own handiwork, and a blank slate to build a custom AR-15 on.
Before building your firearm, keep in mind that all Federal and State laws apply. Educate yourself on restrictions surrounding the features and dimensions of pistol and rifle builds.
A detailed video of the process can be found here. https://www.youtube.com/watch?v=0VHflfI7tVI
Author: Pete Miller