[the count]

this WW2 German 7,65 pistol has a strange problem.. without ammo in the mag. you pull the slide back, press the trigger and you hear the firing pin strike, every time. BUT with real ammo, after the first shot is fired one has to press down on the cocker/de-cocker lever every time or the gun will not fire. i had a gunsmith check it out but he (and he is pretty good) could not figure out exactly what the problem is.....

[rcmodel]

Gunsmith huh?
I know next to nothing about the inner workings of a H38, but:

The problem obviously is that the hammer is following the slide after every shot, so you have to re-cock it manually with the lever before it will fire.

It doesn't do it when you manually operate the slide for one of two reasons.
1. You are operating the slide manually slow enough the hammer doesn't bounce off the sear, so it stays cocked.

Or:
2. Something is going on with the disconnecter / trigger linkage that is not allowing the hammer to cock with the trigger pulled to the rear.

Try cycling the slide manually with the trigger held all the way back as if firing, and see if it stays cocked or not.
If not, it is something wrong in the disconnecter linkage.

If it does stay cocked with the trigger held to the rear, then I would guess the sear or hammer notch is worn, or the sear spring is defective.
The higher speed slide slamming shut when it is fired is causing the hammer sear engagement to slip out and the hammer to follow the slide down.

rc