The T13E1 was a cannon.
ack-ack
A..Ha! for some reason, don't ask me why, I thought it was a derivative of the 75mm Pack Howitzer. I did not know it was a lighter version of the same 75mm Gun on the Sherman et al. To be clear, in the army we define artillery armaments into three categories, Mortars, Howitzers, and Cannon. The categories are based on their trajectories. A tank has a "Gun", not a cannon. Once mounted in an airplane, I really did not know where it would fall in nomenclature wise. Thanks.
