The receiver for the AR series of rifles does not need to be that strong. It doesn't handle any of the pressure of firing the cartridge; it's really just a moun

The receiver for the AR series of rifles does not need to be that strong. It doesn't handle any of the pressure of firing the cartridge; it's really just a mount for the rest of the components. The other components are not considered the actual firearm -- in a legal sense -- so you can just buy those without running into licensing issues (well, maybe local ones). Just add a barrel, a trigger group and other stuff and you're good to go. Printing something that handles chamber pressures is a lot more challenging.