Why shoot WWII ammo?

[lugerholsterrepair]

Mark, I would hesitate to do this...Old ammo of this nature sometimes has deterioration of the mecuric primer. This will oftentimes result in a misfire or delayed fire. Misfires can be dangerous. They can go off seconds later. Delayed fire can be dangerous for different reasons. If the primer is not strong enough it can burn the powder slowly resulting in fantasticly high CUP pressures. I believe this is so because the powder, when burning slowly builds too much pressure before the bullet is able to leave the barrel. Maybe some of our more knowledgable members can elucidate on this odd principle but it is true.
The same thing can occour when live cartridges are put into a vibrating cleaner to clean off the brass. This shakes the powder, breaking it down and making the particals smaller, changing the burning rate, resulting in high CUP pressures. Not every time but ic can and does happen.
Of course you could get lucky and not experience any of these dire scenarios but I just thought you should be aware the possibility is there.

So, I am considering shooting some of this stuff through a chronograph in my "built up" P.38 and a "shooter luger" to determine the ballistics of the round and replicate the ballistics of the round for bullet weight and velocity when I reload.

If you are looking for an exact replication of the German combat round I would think any measurement made 60 years later would automatically be suspect because of variables in deterioration.
Jerry Burney