Joe Bob Outfitter Spartan lower. I think these are re-branded New Frontier Armory lowers, but at a better price. Also, no sales tax! Just add a CMMG radial delayed blowback BCG and barrel and off you go!
https://www.joeboboutfitters.com/Sp...zine-Compatible-Billet-Low-p/jb-spartan45.htm
https://www.joeboboutfitters.com/Sp...zine-Compatible-Billet-Low-p/jb-spartan45.htm