I'd also include the MG 35/36 Knorr-Bremse light machine gun used by the SS. The gun would fire sometimes when the safety was released and the buttstock often would fall off during firing.
It seems like the Japanese type 11 Nambu used a hopper system instead of a magazine or belt. That would be very inconvenient to reload inside an armored vehicle. If I'm not mistaken, the 6.5 mm cartridge it used was too small to make an effective tracer round with the technology of the times.