Edit History

Most of the 50 cal are US Browning M2 HB or the Russian DShK mounted as Anti Aircraft Primary weapons plus anti personal use. American mounts varied over time from pedistal mounts to some as Co-Ax on the T29, T30 and T34 Heavy tank engineering test articles to the Modern CROW system. The French had them mounted as Co-Ax on the Leclercs instead of the 20mm they had before on some AMX series tanks.
Two problems with the 50 cal as Co-Ax ammo count vs. Volume dedicated to it for ready use feed is much larger than a 2,000 Box for a 7.62. Unneeded Long range effects when fighting in Urban areas collaterial damage issue.

As to numbers usable in game Unknown In WoT there are a few in the low tiers of Light Tanks /Scout Cars.
Russian Round https://en.wikipedia.org/wiki/12.7×108mm  
Russian Gun https://en.wikipedia.org/wiki/DShK
American Round https://en.wikipedia.org/wiki/12.7×99mm
American Gun https://en.wikipedia.org/wiki/M2_Browning

Most of the 50 cal are US Browing M2 HB or the Russian DShK mounted as Anti Aircraft Primary weapons plus anti personal use. American mounts varied over time from pedistal mounts to some as Co-Ax on the T29, T30 and T34 Heavy tank engineering test articles to the Modern CROW system. The French had them mounted as Co-Ax on the Leclercs instead of the 20mm they had before on some AMX series tanks.
Two problems with the 50 cal as Co-Ax ammo count vs. Volume dedicated to it for ready use feed is much larger than a 2,000 Box for a 7.62. Unneeded Long range effects when fighting in Urban areas collaterial damage issue.

As to numbers usable in game Unknown In WoT there are a few in the low tiers of Light Tanks /Scout Cars.
Russian Round https://en.wikipedia.org/wiki/12.7×108mm  
Russian Gun https://en.wikipedia.org/wiki/DShK
American Round https://en.wikipedia.org/wiki/12.7×99mm
American Gun https://en.wikipedia.org/wiki/M2_Browning