I have a brand new SBR/Pistol upper in 6.5 Grendel for sale. All components are brand new, never used. I got it all assembled by a gunsmith, and just don't have the need for it like I thought. Aero M4E1 enhanced upper receiver, which has a monolithic rail mounting system. 12" Aero Quantum M-lok rail. 12" Faxon barrel. Seekins adjustable gas block, with barrel properly dimpled for set screws. Toolcraft bolt/bcg.
The barrel is threaded and recessed into the rail by a small amount, but the ID of the rail is large enough to tuck a suppressor or linear comp in. Muzzle device pictured is for illustration only, not included. The upper is located in the north Houston area, or I can ship. $450