Dear rland,

I have two 10.75x65R Collath (Grundig) cartriges with soft point bullets in my collection.
Cases are without headstamps, so the producer is unknown, but i suppose that it may be Sellier&Bellot (Chechoslovakia).

Data:
Base diameter 12.35 mm (0.486)
Rim Diameter 13.86 mm (0.546)
Neck diameter 11.30 mm (0.445)
Bullet diametr 10.695 mm (0.421)
Bullet length 24.5 mm (0.965)
Case length 64.7 mm (2.547)
Cartridge length 87.0 mm (3.425)

Bullet weight 19.0 gramm (297 grein)
Powder weight 3.97 gramm (62 grein)

Powder type is unknown, but I suppose that it may be russian BT-powder. It's burning rate is more or less similar to Vihtavuori N 140.

Cases for this cartridge still produce the Bertram company in Australia.