The M-15A4 National Match Complete Upper Assembly features a triple lapped, stainless steel match barrel and the strongest floating barrel sleeve in the industry. The Picatinny Rail on the upper receiver allows rapid and repeatable interchange of removable iron or scope sights.
Each ArmaLite Complete Upper Assembly includes a forged upper receiver assembly, barrel assembly, bolt carrier group and charging handle assembly. All complete upper assemblies are test fired as complete rifles before shipping.
M-15 Uppers use 7075-T6 Aluminum.
.875 at the Journal (Under the gas block)