AR-15 Maker

Found a site, AR-15 Plus (actually a company called Vida Rica, Inc.), selling kits of partially-completed receivers for AR-15 lowers. Apparently an 80% completed receiver doesn't require an FFL to receive, but is less work to 'smith than a flat or similarly raw part. At the price they're selling the lowers, though, it'd be cheaper and easier to just buy finished receivers, such as DPMS's, for about $210. The only advantage, as I can see it, is for someone who wants to build their own—or to fly under the gov'ment's radar.