I bought a Russian 25mm AA battery to act as AA against low/mid air-strikes and also since it came with a small number of rounds of AP ammo I thought it would be decent emergency AT. The issue I am running into is that when direct firing at armor (PzIII's and 222's) it is only using HE rounds. I do not recall reading anywhere that guns marked AAA were restricted to not using AP against ground targets...did I miss it? I did a quick search of the forums and found nothing. I swear in the past I have successfully used AA guns with AP ammo against armor...but maybe I dreamt it. Any info or clarifications greatly appreciated, thanks!
AA guns can certainly use AP ammo against ground targets, I have enough brewed up scout vehicles to testify for that.
At what range are you engaging those targets? If you are at longer range, then there is a possibility that the computer selects the HE ammo in preference of the AP ammo, due to the later having poor penetration at longer ranges.