So I have this nagging question in the back of my mind: what is the legality of building your own firearms at home? I know there are FFLs that pertain specifically to gunsmiths and manufacturers, but I don’t know the details on these. I do know that FFLs are a pain in the arse to get. So, say you’re a person eligible to buy and own a particular type of firearm (you’re over 18 and aren’t a felon and you want a rifle), but you want to build one for yourself from scratch. The weapon you want to build is within local regulations (you live in the Yeller, uh, “Golden State,” of California and you want to build a 20” bbl, 7.62x39, straight-pull bolt-action, 5 round fixed box mag, fixed stock rifle with no particular bells or whistles, and by “from scratch" I mean from parts from Lowe’s and Pick-your-Part. It is possible) but you have no FFL. Would it be legal to build this? Would you have to register it in any way? Would you be able to transfer it like a normal firearm? How do these rules apply to handguns and shotguns? Am I screwed for living in Cali? Am I screwed in general? And any other relevant questions I haven't thought of...