I will be the first to admit I am not an AR expert, and frankly the massive volume of stuff on the internet is confusing me--so I hope somebody can help me out here.
I just bought a new PSA 9mm lower that takes Glock mags, and I would like to purchase a compatible side-charging complete 9mm upper. Does anybody sell a complete upper that will function with the PSA lower? If not, what would I need to put one together?