Its not a minimal gain i can assure you.. in any bullet weight... he stated he was "building a 7RUM" so if the Building process didn't involve maximizing the rum for what its capable of then I guess your not actually building it!!! even with a 168 berger there will be a substantial velocity gain and the original post he wanted and unbiased opinion which i gave by having had both "built right" I didn't bad mouth either, hell i like the STW but i stated it by fact of having them both "built right". but yes FACT is the 7rum in any form will out perform the dandy 7stw.
it boils down too powder used .. the ole tried and true just doesn't work in big cases to its full potential