My "Sporting Ammunition Catalogue" by ICI of date unknown lists Kynoch ammunition with a load of 40grs smokeless with a 270gr solid, soft or split bullet for the flanged 375 x 2 1/2" cartridge and a load of 43grs smokeless with the same range of 270gr bullets for the rimless 375 x 2 1/2" cartridge.

The ballistics for these two cartridges are also listed if you want that info.