Finland's Prototype Belt-Fed GPMG: L41 Sampo
20m
During the 1930s, there was interest in Finland in replacing the Maxim heavy machine gun with something handier and more mobile. There were experiments with large drum magazines for the LS-26 light machine gun, but these were not satisfactory. Aimo Lahti began to work on a gas-operated GPMG, but lack of funding and competing priorities led to it having slow progress until the eve of the Winter War. By the time the gun was completed and the first preproduction batch ready for troop trials, the Continuation War was underway.
Twenty eight of the L41 Sampo machine guns were sent out to a variety of units for field testing in the fall of 1942, and the guns were generally well liked, although not perfect. Before improvements and full-scale production could begin, though, the Finnish military was basically distracted by an alternative possibility of procuring MG42 receivers from Germany and building them into complete guns in 7.62x54R. At least one such prototype was completed, and that project caused the L41 program to stall. By the time it might have progressed, the war was going rather badly for Germany and the possibility of getting receivers was basically gone. The L41 never did see further refinement or production, although the trials guns remained in service with their units, in a few cases right until the end of the war.
Mechanically, the L41 is a fascinating hybrid of Bren/ZB and Maxim elements, and incredibly sturdily built. Only seven are know to survive today, six in Finland and this one in the UK. Thanks to the British Royal Armouries for giving me access to it to film for you!