Pardon me if you already know...
Whatever upper you get, be sure to hone or at least check the face before locking that barrel in. Also, sometimes the barrel extension requires shimming or sleeve retaining compound to mate it to the upper firmly.
My last assembly (Aero upper/lower) was so close but not close enough. Didn't have any .0005 shim stock so I used sleeve retaining compound. Permatex stuff is good up to 400f.
Whatever upper you get, be sure to hone or at least check the face before locking that barrel in. Also, sometimes the barrel extension requires shimming or sleeve retaining compound to mate it to the upper firmly.
My last assembly (Aero upper/lower) was so close but not close enough. Didn't have any .0005 shim stock so I used sleeve retaining compound. Permatex stuff is good up to 400f.
SI VIS PACEM, PARA BELLUM