Polish OOB2 corrections/suggestions (v.6)

[PvtJoker]

Ammo-related question:

You write here http://derela.republika.pl/weap.htm#am that the Polish army had AP and API ammunition for the 7.92mm machine guns. Were those ammo types commonly issued to armored vehicles and do you have any data about their armor penetration capabilities? Is there any evidence that they were used against German armored vehicles in 1939? I suppose they were of conventional design with steel core?