Exceptional durability and dependability built right in. Designed and manufactured entirely in the United States, these Anderson-made upper receiver assemblies and stripped upper receivers are crafted from a 7075-T6 aluminum forging and machined with M4 feed ramps with a Type III black hard-anodized finish. All Anderson uppers are machined to military specifications and standards and are compatible with multiple AR-15 calibers. Pairing with an Anderson-made lower receiver enables you to complete your next build with ease and confidence.