Re: Bug? AAA fire from emplacements
Oh yes - fortification armour is not steel armour.
Forts are assumed by the game to be concrete logs, whatever. They are semi-permeable to all HE fire, the larger the armour value, the less so. The larger the HE Warhead size, the more so. The steel value is only relevant if firing at them with AP, Sabot, HEAT - i.e. anti-tank ammo.
Feel free to set up a test scenario with some riflemen shooting up a fort or bunker (outside range of any AT weapons they may have - the AT weapons do different effect as mentioned). Eventually they will start to get casualties on the fort's crew. Especially when the hit chance rises. Don't complain about it - that is an original SSI game design decision and it's been baked into the code from SP1 days.
The fortification classes were never meant to be flak towers. That some of the OOB designers decided to make some AA equipped is their own design decision. They are only armed for local AA defence.