I posted other day about issues w 10.5” 300blkOut upper. Hav lots more details now. 10.5” with Pistol gas system. Mags run great on 223 uppers. Using 20rd Colts. Lubed BCG hard w Lucas. 10.3-11.0 gr 1680 w 208 Amax’s lded 2.230”. Shooting suppressed w SiCo Omega. 11.0gr is still subsonic and will lock bolt bak. Ejector seems weak? Seems to not eject the empty as hard or far as other uppers I hav. Hav not changed buffer or spring. Would like for it to shoot supers and subs both reliably. Any other ideas? Thanks