this is not a norma made case but a german pre war and Norm means Normalisiert = normalised. never see this RWS hollow point bullet before but its factory made, no doubt about it.

got the measurments for this cartridge

oal 78,60 mm

rim diameter 11,83 mm

base diameter 11,85 mm

shoulder 11,70 mm

case neck 11,50mm

a little bit longer than the municion.org drawing but they had probably another load with another bullet

notice that the mother case 8x57 had than a maximum diameter of 11,88mm but on paper brass go up to 11,95 mm. I had this problem once when making brass for the 9x57 and 9,3x57 ( pre ww1 M 88 and 1927 made Husqvarna) by using new 8x57 cases. resized the cases with my brand new die sets and they dont chamber until I turn down the brass on the lathe a little bit so it measure under 11,88mm.
could be the same with 30 06 or 35 whelen cases in your Kettner rifle.

any stuff about the 10,75x61 is hard find! another friend found this in an old cartridge auction catalog.

he will looking for more

the measurments in the DWM case book are hard to read for me also, I will ask for this again and for the bullet weight.