Knight's Armament CRS-2 5.56

The Knight's Armament 5.56 CRS-2 is the balanced full-size choice for a rifle already set up with a KAC 5.56 QDC muzzle device. It is 6 inches long, adds 5.4 inches beyond the bare muzzle, and weighs 15 ounces. KAC publishes 143 dBA one meter left of the muzzle, 136 dBA at the ear, and second-round flash of 0.1 mcd*s. Those figures point to useful sound and visual-signature control, but they are manufacturer measurements rather than a PEW Science Suppression Rating.

The CRS-2 is not the older, heavier 5.56 QDC/CRS-PRT that PEW Science tested. Treating the two as interchangeable would overstate the evidence for this model. The CRS-2 fits every KAC 5.56 QDC muzzle device, which makes it an easy choice for an SR-15 or another host already committed to that system. KAC calls for at least 0.200 inches between the handguard and the rear of the muzzle-device index pin so the locking collar can close fully. Some 11.5-inch SR-15/16 MOD2 CQB rifles with a 10.75-inch URX4 need a different QDC device, a shorter handguard, or careful shimming to create that clearance.