Quote:
Originally Posted by Pibwl
37mm SA-18 couldn't be all that rubbish, if Polish armoured cars wz.29 recorded several destroyed armoured cars and light tanks, including Pz-I with 13mm armour ( http://derela.republika.pl/wz29.htm ). Most probably they had standard AP shots, and I doubt, if all cases were point-blank.
I've just read a Polish source, that steel 37mm bullet pierced 15 mm of cast iron at 1000 m (which is of course not armour, though). All in all, I feel, that range 4 should be increased a bit, maybe doubled. |
The material properties of (grey) cast iron are quite different from any quality armor steel, most notably its tensile strength and toughness are much lower even though it's pretty hard.(White cast iron is very hard, but I doubt they used it for testing). So I can't even guess what that penetration might be against armor steel plate of any hardness.
As for the combat experience, it is of course undeniable. Yet even that web page mentions that penetration was only 12mm at muzzle. Are you certain that the Polish Army did not develop an improved AP round for the gun some time in the late 1930s? The original French AP was late 19th century design and probably some improvement (e.g. something like 30% better penetration) could have been had just by developing a more up-to-date AP or APC ammunition.