Japanese Long Campaign

[stormbringer3]

I am running a Japanese long campaign and the the tank unit I use has both HE and AP shells. However, whenever I target a Chinese armoured car, armoured truck, etc. the Japanese unit always fires HE instead AP and as a result they are almost impossible to kill. I am in the 1931-1932 era. Is this HE firing against armoured units normal becauce of the era or a possible flaw? Thanks for any info.