I can't imagine why the Americans should have been surprised at the ability of Germanicon bullets to penetrate that light armor. Except for the engine louvers, the M3 Personnel Carrier (half-track) had only 1/4" armor and the standard U.S. AP round will penetrate (up to) 1/2 inch of standard armor plate and 3/10 inch of face hardened armor at 200 yards.

Jim