I've used the forged lowers from American made tactical. They are good to go, but I see they've jacked the prices up $20
Their billet 80% lowers are junk though. Don't buy the billets. I sent 2 of them back for being out of spec. They didn't even want to here it. Bet $ they turned around and resold them to some poor smuck. The rear take down pocket was to wide by like .007. Can't put metal back so they'd have been sloppy as hell.
I did build a large frame billet from them & again it was out of spec. Mag catch to low etc. It runs like a champ now but was a total PITA to get ironed out. I've got a long detailed thread on that large frame build.