Lets see, for the four-hundreth million time.. here is the armor specs for a Panzer IV H
Hull
Front: 80mm/ 14 degree slope (bottom), 10 degree slope (top)
Side: 30mm / 0 slope
Rear: 20mm/ 11 degree slope (bottom), 8 degree slope (top)
Top: 10-12mm/ 85-90 degree slope.
Turret
Front: 50mm/ 10 degree slope
Sides: 30mm/ 30 degree slope
Rear: 30mm/ 15 degree slope
Top: 10mm/ 90 degree slope
From
http://members.rogers.com/admfisher/html/pz4.html#hNow granted, if our 37mm "duel purpose" gun was a mortar, I might be able to see it knocking out tanks by going through the top armor. However, as far as I know it is a direct-fire weapon, not a mortar.
If you can find me a "duel purpose" 37mm gun capable of penetrating 50mm at 1,000+ yards, then I'm wrong.