Great quality upper - Aero Precision M4E1 Threaded 11.5in 5.56 w/ATLAS R-ONE Handguard Upper Receiver with Flash Hider

This is a good quality upper for a pistol build. Handguard is nice, and well made and pairs smoothly with the upper reciever. The barrel has good accuracy. I put a NiBr bolt in it and it runs like a champ. Can probably buy a fully assembled pistol for less from bigger manufacturers but it was fun to assemble my own system. Now part of my favourite AR.