Less ammo is stupid imo. Why not make panthers randomly blow up to simulate their unreliability?
Even though both are historically correct things, I find less ammo plausible, but Panthers blowing up randomly? I don't think so for two reasons:
First, have you ever seen a tank blow up if it just happened to have it's gearbox broken? It may get abandoned or just sit there and defend fanatically until someone blows it up.
Second, BF2 doesn't support randomness. IIRC this was pointed at japanese knee-mortar/pzfaust thread.