I have researched 100% of the modifications from T-55A but noticed when I wanted to enter a test drive that I cannot choose the HEAT round as it doesn’t exists??

I have researched 100% of the modifications from T-55A but noticed when I wanted to enter a test drive that I cannot choose the HEAT round as it doesn’t exists??
No more need. I found how to use the HEAT round. I had to select it.
Yet still, could be made more intuitive and easier to select it within a battle.