The Czech ZB-26 and improved ZB-30 were the most widely used LMG in WW2 in terms of nations. Of European Axis combatants, only the Finns and Italians didn't normally use them, even the Germans used very large numbers (they were the main SS LMG early war). They were the main LMG of the Chinese and Jugoslavs and they both produced their own as did the British, this time in .303" as the Bren (aka ZGB-30/ZGB-33). The Japanese used their own version, but only as a tank MG. Their Type 96 and 99 infantry LMG, though they looked externally similar were internally quite different.
While in reality there would be a problem in mixing ZBs and Brens due to the different ammunition, that is below ASL's level and the counters should be interchangeable. Personally I dislike the B11 given to the ZBs as it was a very, very reliable gun. Indeed a ZB-26/30 due to its use of rimless 7.92mm ammunition was slightly less likely to jamb than the Bren using .303 rimmed ammunition. But that's me being odd and that (B11) was decided a couple of decades ago. BFP produced a normal (B12) version in PiF in Axis Minor as well as a German LMG that covered the ZBs.