An AR15 Upper Receiver, also commonly called an “AR15 Upper”, or simply, an “Upper”, is the heart and soul of your rifle. It houses your bolt-carrier group, your barrel, supports your handguard or rail system choice, and wears your optics on top. When it comes down to what kind of rifle you are building, those decisions are made in your upper receiver. We build our own upper receivers in-house, to exactly how you order it, so you get an upper to fit your exact needs.