6315KM-S, 9mm is a short Key Micro muzzle device for Dead Air Silencers 9mm sound suppressors. At 2.063" long, it's tiny compared to the 6315KM (2.4"). Though the 1/2 x 28 6315KM-S, 9mm could be installed on a 223 AR, its much abbreviated length and larger bore size (0.385", or 9.78mm) would mean reduced performance in the way of flash signature mitigation and muzzle rise compensation. Like 6315 on which it's based, 6315KM-S 9mm has asymmetric ports to optimize muzzle rise compensation without creating obnoxious concussion and noise, its 3 and 9 o'clock ports are slightly smaller and shorter, the design forces more gas to be vented through the 3 upward facing ports. Compatible with Dead Air Silencers Key Micro 9mm sound suppressors.