Luth-AR Mark 12 Kit Minus Lower Receiver w/ Collapsible Stock 5.56mm 27in 18in Government Rifle 1x9 1/2x28 Picatinny Key MOD A2 Flash Hider Anodized. 56 Complete Mark 12 Barrel Kit features an 18 inch Mark 12 5.56mm barrel and a 15in KeyMod short...