I was surfing through Dorleac & Dorleac's web pages when I came accross an Austrian drilling with an unusual rifle caliber, a 10,75 rimmed I believe. Here's the link, go down to Drilling Viennois, Springer and there's a photo of this unusual rifle (for sale for 2,500 Euros by the way.) It's the last of the 50 used guns posted so you may have to open a few pages before you get there.

http://www.dorleac-dorleac.com/pgs_eng/nos_occasions.ph...structeur=&offset=45

It could well be it was made for the Swiss market. I remember reading that in at least one Swiss canton that there is only one legal hunting round, which is an old BP number (not sure, but I think it's an old 450/ ? BP) around the 10.75 region.
Someone out there is bound to know the actual round.

It sounds like a nice gun.

it was wictor collath that made the round, i dont have the specs for it but it seems like a rimmed version of the 10,75x68 ,very similar like the 9,3x62 and its rimmed twin the 9,3x74. loaded a little bit down due to the chamber pressures. i have more about in a book, ill dig it up and see what i can find about it.

Wink, the 10.75x65R is a rimmed cartridge with a streight case, that is 2.56 in length, and cases can be made from 45 basic. Turn the rim to .542", and back chamfer.cut case to 2.6", and anneal. Form in full length die. Trim to length and chamber. fireform case in chamber. Proper bullet dia is .424.

General comments:

The largest of the Colath-developed cartridges, this one this one has a straight, rimmed case. It was loaded with a 205 gr soft point bullet, and the only load I could find for it was 305 gr lead, 41.3 grs IMR3031

The Colath cartridges are collector items, and rifles for them are uncommon. Case dimentions are not a lot different from the 405 Win, and one could probably use this as a guide to work up load data!

This info is from two sources, HANDLOADER'S MANUAL OF CARTRIDGE CONVERSIONS , and CARTRIDGES OF THE WORLD,6th edition

The vendor has confirmed that it is a Collath cartridge and not a Grundig cartridge. Thank you all for your assistance. Anybody have any idea what kind of velocity one could hope for with one of these cartridges?