Why the FUCK do you need to be 21 to purchase a stripped lower receiver??! I was all excited to start my first build. Ordered an Aero stripped lower and was doing a bunch of research to find the best, most cost-friendly parts. Then, I hear that you must be 21+ to pick up a STRIPPED LOWER from an FFL. That is the dumbest fucking shit I have ever heard. I mean, what's preventing me from taking the lower off of my legally owned AR and slapping a short barrel on it? Literally nothing. Fuck this. Guess I'm either gonna have to wait half a year until I turn 21 or buy an 80% lower and figure out how the fuck to work with that.
Here is my obligatory gun image so this doesn't get taken down.
And yes, I know this is an Arby's you fucking 'tists.
Update: Thanks for all the advice and help. Just ordered two 80 lowers and a jig. Time to get to work boys.
Buy an 80%, get it shipped to your door, and finish it on a mill. Unless you're in CT or HI you should have no problem.
I live in a relatively non-commie state so I'm considering doing that. Not very mechanically savvy though so I got a lot of research to do. Also mills/drill presses/routers are pretty expensive but I guess it's worth the investment.
Even a cheap jig makes it stupid easy. I have an 80% Arms easy jig 1st gen, it was like $75. You need a router ($100-$150) and a drill press ($80) to do it properly (if you're getting a metal lower, you can probably do a polymer one with one of those dremel press stands).
Takes a while to mill out the aluminum (plastic is much faster) but it's not difficult at all. I was wary of it, but buy a jig and watch a couple videos.
Worst case, spend another $40 on a second 80% lower and then you can have either a practice piece or 2 ARs depending on how difficult you find the milling process.
I may or may not have seen good results from just an old craftsmen drill press with an X Y table from Horrible Freight. The purists will REEEEE, but as long as you keep it wet with wd40 (yes, wd40) and go slow the results are very good. But that friend died in a boat wreck with everything on board including the press.
If going this route, check your chuck for tightness often. Having a bit drop can be disastrous. Also make sure to take passes the correct way for the rotation of the bit. If it chatters excessively, try taking the pass from the opposite direction.