Could anyone ID this 7.92x57 blank cartridge?
Unfortunately I can not tell more than is visible on the images.

All I can tell you about your blank is that it is a typical German Platzpatrone 33 (Blank Cartridge Model 1933), and with one “Sorte Ring” on the case, indicates it was the first reload of that case.

The absence of a headstamp makes it about impossible to tell much else. Without the box label, you cannot say for certainty, with any German loading, who actually loaded it (except in cases where from box label study, it is known that a particular load and particular headstamp are always loaded at one particular factory, perhaps the one on the headstamp). Remember, the German headstamp from the post WWI period in particular only identifies the case maker and case information, not the loading factory or the loading lot number.

The Germans made unheadstamped 7.9 x 57 for various reasons - Polte made quite a bit of it, being found in boxes for Romania, and among Portuguese ammunition, among other things. Any of those cases fired in testing or practice firing could later end up as a PP33. Also, reject cases were used for making blanks. A much less likely thing is that the blank was made on a case rejected because it missed headstamping. I give this as a possible scenario, but one I consider very unlikely.

Unheadstamped cases are found in brass, copper-washed steel and lacquered steel, and in various loadings.

I hope this is of some assistance. Unheadstamped cartridges always pose a problem of pinpointing identification, even when the country who loaded the cartridge is known. You can’t always even tell what country the case was made in, much less what factory. It is a good bet this case is German, but not positively so. German PP33 loads are found in cases from Poland and Czechoslovakia at least, and probably other German-occupied countries where the 7.9 x 57 cartridge was being made.

John, thanks a lot, so at least we can tag it as German.

Any other opinions?

Looks also German to me.