Does this loss of ammo include cargo ?
If not, what would stop people from just putting a large supply unit in each stack ?
Actually, nothing stops them. But we've tested that and found it is very difficult to achieve effectively. Usually the supply units get attacked and often killed before the combat units are able to protect them. Remember that a combat unit without ammo does not fit the stand-off requirement. A supply truck in the same hex as 6 infantry is attacked without protection if all 6 infantry are out of bullets.
Did some -normal- test... works fine now.