Hello eagle27,
Thanks for the reply.

Very interesting .. What you say is 98% spot-on ... However, you might want to read the details about sectional density in the "performance" chapter on the 10.75x68 cartridge in Pierre van der Walt's book "African Dangerous Game Cartridges". You might be surprised. That book also gives much loading data for the cartridge using 400g bullets, with several examples at 2140+fps. Same holds true with loads listed in Load Book. We are fortunate to have much improved powders and bullets and loading data available today for those who may be interested in using their 10.75x68 rifles for Big Game.