The velocity difference between the 7 STW and 7 Dakota
are almost the same. You should be able to push a 180g bullet between 3000 - 3200 out of a 28" barrel. I prefer the 7 Dakota as it headspaces off the shoulder rather than a belt. The only down side is the brass. Your stuck with Dakota brass which is a little pricey, but good quality. I have heard of a few guys who have necked down 338 Ultra Mag brass down to make 7 Dakota brass. From your Remington 700 7 Mag I would suggest getting a sako extractor installed. The Dakota brass is based off the 404 Jeffries case and it has a .545" case head rather than the .535" magnum case head. The factory extractor grove isn't quite cut deep enough and if you tried to close the bolt on a case with the factory extractor you will chew the brass off the rim. With the sako extractor it just simply snaps over easily. The feed rails will need to be opened up slightly about .030" - .040" from the 7 Mag to accept the Dakota case too.