If you’re looking for a silent BCM MCMR 11.5 inch AEG, PrimeMech Airsoft has one that is VFC Colt Licensed. It features an Aimpoint T2 Hollywarrior, a Surefire M600, and a Dead Air Sandman K silencer by 5KU, along with a Unity pressure switch. The parts list includes a Leviathan by Jefftron, a Brushless 20k by Warhead, a 12:1 SSG, and a MagicPad. It operates at 1.2J with 0.28g. This setup should meet your needs perfectly.