Am I opening a can of worms here? I think I am...M113...

[B.T.]

During my time in the Bundeswehr, we usually called the M113 "Panzer", like in phrases as: "No smoking in the Panzer!"

But "Panzer" is not clear as definition: The Tank (= Main Battle Tank) in German is: "Kampfpanzer".
The IFV/CAV and even the APC are called "Schützenpanzer" in German.
"Panzer" is used as a word for all kinds of tracked vecicles in German.

Therefore it was not completely false, but on the other hand: Everybody knew, that the M113 was not a "Panzer" like the Marder (and the Marder is a true "Schützenpanzer"). It was used as a kind of mocking phrase.
When we were introduced to our workhorse, the NCO explaining the M113 mentioned, that the trim vane would serve as a kind of additional armor. I've never read something like that afterwards, but in a way he was not for from reality. That special NCO even added that you could saw a M113 into pieces with MGs in 7,62 NATO, given time and a lot of ammo. Still don't know, if this is true.