AP rounds are often a bit hotter than standard loads because of the way an AP (rifle caliber) round works, but they would not be hot enough to damage a gun. No one ever said the Germans were stupid and it would be pretty dumb to issue ammo that would damage or disable a firearm in combat.

FWIW, an AP round does not penetrate armor from sheer energy, like punching a hole in a tin can. What happens is that when the bullet strikes the armor plate, its kinetic energy is converted instantly into heat*, which softens and often actually melts the armor at that point, allowing the bullet core to penetrate and do damage to what or who ever is behind the armor.

If the armor is thick, the melting/softening will not extend far enough in to let the core penetrate, and the core will stick in the armor. IIRC, there is a Germanicon tank at Aberdeen with a dozen or so .30 cores stuck in its turret armor. Apparently some GI believed that AP mean AP and kept trying.

*The same conversion of kinetic energy to heat is what bulges barrels when a bullet meets a barrel obstruction. The barrel is not bulged solely by the pressure; it is softened by the heat first.

Jim