Receivers Machined from Aluminum Forgings 7075-T6 Receivers Hardcoat Anodized per MIL-A-8625F, Type III, Class 2 Staked M4 Lock Nut USGI H Buffer (1 USGI Tungsten, 2 Steel) Low Shelf for RDIAS installation Low Shelf for Accuwedge use Fire Controls marked SAFE and SEMI BCM QD Sling Mount End Plate