Thanks very much - I appreciate the replies. 30-40 had actually crossed my mind - it would be supremely useful and like you said, it's nothing to sneeze at. 220 grains at 2200 would keep going, and going, and going...

The allure of the 400/350 keeps pulling at me, hard. Probably due to John Taylor's book as much as anything else. It's not a practical thing at all, of course, and there are better options. But the 9.3X74 is a little too common to get me excited. I would like to know what chamber pressures you get with all of these options, but I can't seem to find that information anywhere.