From Cartridges of the World,2nd Edition

Bullet diameter .367
Neck diameter .375
Shoulder diameter .437
Base diameter .483
Rim diameter .572
Case length 2.273
Ctge length 3.437

Loading
40-41 grains Cordite
Bullet 300grn MV1950 ME2537 Purdey load sp
Bullet 314grn MV 1900 ME2520 W.R. Load sp

Barnes states it is similar to the .35 Winchester in power

From Griffin & Howe's website


They are on sale at Midwayusa
Thick rimmed Westley Richards http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=401558
Thin rimmed Purdey http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=390334

Pete