USED AT3 Tactical AR-15 Slick Side Billet Upper Receiver Black AT3-UPPER-1. These AR15 Upper Receivers made by AT3 Tactical have no forward assist a dust cover and match with mil-spec lower receivers for a reliable fit every time. The AT3 Tactical AR-15 Slick Side Billet Upper Receiver has M4 feedramps and .250 takedown pin holes for compact packing with a swift trigger. Pick up an AT3 Tactical AR-15 Slick Side Billet M-LOK Upper Receiver for your rifle build and add some extra flare to it. Specifications for AT3 Tactical Tactical AR-15 Slick Side Billet Upper Receiver: Manufacturer: AT3 Tactical Fabric/Material: 6061-T6 Aluminum Caliber: 6mm ARC .350 Legend 5.56x45mm NATO .300 AAC Blackout Gun Make: AR Platform Gun Model: AR-15 Hand: Right Weight: 7.1 oz Features of AT3 Tactical Tactical AR-15 Slick Side Billet Upper Receiver M4 Feedramps .250 takedown pin holes Low-profile brass deflector No Forward Assist Package Contents: AT3 Tactical Tactical AR-15 Slick Side Billet Upper Receiver Dust Cover What firearm models does the manufacturer say AT3 Tactical Tactical AR-15 Slick Side Billet Upper Receiver is compatible with? The manufacturer suggests that AT3 Tactical Tactical AR-15 Slick Side Billet Upper Receiver is compatible with AR-15AT3 Tactical AT3-UPPER-1: AR-15 Slick Side Billet Upper Receiver Black