Yes, I know this isn't strictly metalworking, but there are plenty of
gun people here.
A howitzer fires, with elevation 45 degs. So the shell exits, pointing
upward at 45 degs., spinning. When it hits the target, it is (to 1st
approximation) falling at 45 degs., but the spin should have kept it
pointing upward. This means it would be flying sideways-on.
This sounds wrong to me, but where is the error?