A mechanism for loading suspended loops of linked ammunition onto rails of an ammunition magazine includes a guideway and a carriage. The guideway has cam surfaces and cam slots each extending vertically from a lower portion of the guideway and curving near an upper portion of the guideway toward the rails at a loading end of the magazine. The carriage includes a support block slidably received by the guideway and a tandem bucket mounted on the support block by a linkage. The tandem bucket includes inner and outer followers engaging the cam surfaces and cam slots. The tandem bucket is horizontal and may be loaded with two adjacent rounds of a belt of linked ammunition when the carriage is at a lowered position. The carriage may then be raised manually, wherein the tandem bucket is articulated by camming engagement of the followers to a vertical orientation to deposit one of the two rounds onto the magazine rails with the other round and trailing rounds suspended therefrom.