Achilles gun depression should be -10 Degrees.(Photos attached)

The_Chieftain: With competing depression angles available on paper, I decided to settle the matter by climbing into a 17pr M10 and depressing the thing as far as I could. (It was the one at MVTF), it stopped at about 5 degrees. That's what got implemented. The British Army would not have put a stop in for the fun of it, the best thing I can think of would be an estimation that the turret and mount simply wasn't expected to be able to handle the upward component of recoil from the larger round.