[Edward Tinker]

The carbines were loaded hotter, but not much hotter.

The black cartridges were "proof" cartridges, meant to test a luger, but not for normal use.

And Tom, I think we are getting onto the same sheet of music. What you need is to reload ammo that takes alonger time to burn going down the barrel, thus increasing velocity, rather than burning out and slowing down in the barrel.

Also, another detail, the "true" carbines used a special extra spring under and attached to the frame to take the extra recoil of the hotter round.

Ed