We all miss the hell out of our Dads when they go, even if we didn't get along all that well when they were here. It's just so hard for OUR generation to understand what THEIRS went through..... and I grew up with my elementary school 2 blocks from a major target.... and Comrade Stalin threatening us half the time.
As you say, there are just so many unanswered (and all too often unasked) questions. My Dad was in a Hurricane squadron and then was Chief Inspector (Instruments) at Aircraft Reapir in Edmonton, where they rebuilt several hundred P-39s for Mother Russia. When I miss the hell outta him, I watch "The Battle of Britain": they used one of HIS Hurricanes in the film, one he serviced every day with 133 Sqn in Boundary Bay and Tofino.
But we can never know the challenges that that generation faced, no matter how much we read and question and even experience ourselves.... because the ties have changed. Look back with respect.... it's all we can do now.
As to 9mm Para in a .38S&W revolver, you have to remember that the mil-spec load was originally a 200-grain bullet (the Webley "Manstopper" loading, basically) and this was changed to a 178-grain RNFMJ slug just in time to get away from any Hague Convention charges. Everybody knew that German 9mm was loaded very hot and I would think they avoided the "black ball" German SMG loads like the plague. Of course, it might be nice to avoid those pretty green Proof rounds, too! But guys who were actually in combat have told me that they stayed away from the German ammo because it was too hot for our guns.
Still, if you have half a dozen guys to shoot..... and no .380 MkIIz rounds.... and a whack of 9mm pistol loads or Glisenti ammo.... it would be rather tempting. Nice round holes don't look good in my jacket, anyway and, if they leak, it's even worse.
BTW, all those revolvers had a special rifling pitch to accommodate the 200-grain bullet. Wonder why nobody makes tha ammunition? You can't even find an inexpensive 200-grain mould! Market there for somebody smart...