Tank vs. Cannon

[Rupert]

Originally Posted by Anthony

22mm of WWII armor steel should be around DR 60 (penetration is normalized for RHA being DR 70/inch, and I would expect early tanks to be comparable to RHA).

Not sure about the penetration of the 12 lb gun, though. You can essentially view it as a 144 weight (5.24*scale) 12 gauge shotgun (12 gauge means a spherical lead ball would be 1/12 lb, 12 lb means a spherical lead ball would be 12 lb), and 12 gauge slugs are generally stopped by level IIIa armor (DR 12), so I'd be tempted to assign a (0.5) armor divisor.

I'd be concerned about spalling, rivets, and from the shock of impact. Getting hit by a 12 pound ball of iron moving at high sub-sonic speeds is going to make quite a bang. The armour plates might also simply get bent and deformed to the point where they fall off.

On the other hand, if the ball hits at an oblique angle, it's probably just going to bounce off and do nothing other than make a loud clang!