After doing some more careful measuring, it looks as if my 7 Lapua Improved project will net me somewhere around a 6 grain increase in nominal powder capacity over that of a 7 RUM. That's good enough for me, especially with the advantage gained in brass quality. The increase gained with the various 30/338 Lapuas of our members over the parent case seems to be somewhere around 7 grains. I would be most interested to learn of the amount of gains achieved with other common "improved' cartridge projects. Who has good data on the 300 Tomahawk project, before and after?