I dont have any for sale but I can give you some advise
1) hahn mag block is the best IMO dont settle for anything less it will be a headache
2) I run the ar15 hammer with a ramped bolt
3) mags get colt or metalform if you want last round bolt hold feature or modofied uzi if you dont and stay away for pro-form they are junk
BTW I have a pro-form mag if you want to try it just dont throw it at me when it doesnt work !
Thanks for the advice! It's always better to talk to someone who has already blazed the trail.
I have another question: Is the upper receiver for a .223 the same internally as the 9mm upper? (I don't care about the case deflector and the mini port door.) I have an extra .223 upper and I'd like to avoid buying a stripped 9mm if it is internally the same.
yes the upper rec is the same just the 9mm doenst have the hole for the gas tube or F/A some people plug the hole for the gas tube others dont they also make a plug for the F/A if you want to leave it out