Abstract: An apparatus includes a firearm magazine configured to be selectively received by, and coupled to, a firearm. An ammunition spring is received, at least in part, in the firearm magazine. A spring-adjustment assembly is mounted to the firearm magazine, and is also interactable with the ammunition spring once (A) the firearm magazine is received by, and coupled to, the firearm, and (B) the firearm magazine is removed from the firearm. The spring-adjustment assembly remains with the firearm magazine so that the spring-adjustment assembly is not inadvertently lost or misplaced once the firearm magazine is removed from the firearm.