HRT-Style Colt 11.5-inch on a Rock River Lower with Geissele MK4

A regional-SWAT-inspired 11.5-inch carbine: a Colt cage-code upper, Colt barrel and carrier under an ODG Geissele MK4 Federal rail, on a Rock River lower. An Aimpoint T2 on a Unity mount, Troy HK-style sights, a SureFire Scout Vampire, a Troy VCG, ODG Magpul furniture and a Dead Air CT5P complete it.