Having caught the bug, I'm researching the reloading project after the next, which is 7x57R with a 150gr bullet. The only manufacturer data I've found is from Norma, which is fine, but they don't list Viht N140 as a powder in their data, which is what I'd like to use. This is because I already have a load of it, but more to the point I'm planning to develop a suite of rounds in 7-08 and 7x57R that use the same powder and bullets for the sake of economy and consistency. Once that's developed, I'll leave it at that and get on with some actual proper shooting!
Anyway, back to Norma, who do recommend a minimum of 39gr of Norma 203-B and a maximum of 41. Now from the burn rate chart, and I know that's only a vague guide, Norma 203-B and Viht N-140 seem exactly the same. I realise that there are other things in play here and that one shouldn't assume direct substitutability, but I just wondered whether anyone here had had the opportunity to compare the two and what they'd concluded.