I can't think of anything a subsonic .223 can do better than a .22lr or .300BO. No matter what, you will have to build or buy a dedicated upper so why in the world would you stick with a .223?
As for the noise, wanting a hollywood quiet AR that cycles is not going to happen.
Personally, if I were to be hell bent at launching .22 caliber projectiles at subsonic speeds and doing so quietly, I'd get a threaded bolt action .22lr.
Last edited by wareagle700; 04/14/15.
