Was alerted that there's an omission in Trench Hammer.
This will be updated when I get a chance, but when firing field guns at tanks, they follow the same rule as tank mounted guns (do not apply the +3 hit penalty for armored targets).
Perceptive readers will also note that firing at tanks in October Hammer is a bit easier (+2 to hit penalty) compared to the +3 in Trench Hammer.
This is intentional. It accounts for the somewhat modest performance of tanks in the civil war and the fact that limited supply situations meant that more modest damage could be viewed as cause for retreat.