A cam race comprising a hardened material (harder than a material of an upper receiver) is provided to increase durability of a firearm. The cam race is fit within a groove within an interior sidewall of an upper receiver of the firearm. The cam race comprises a body that is fit within the groove, and a plurality of fastener pins extending away from a rear face of the body that fit within corresponding through-holes of the upper receiver. Distal ends of each of the fastener pins are deformed to form a riveted connection between the cam race and the upper receiver. The cam race defines a slide face along which a cam pin of the firearm slides during a firing process, thereby increasing the durability of the firearm against undesired formation of defects within the interior sidewall of the upper receiver.