Why Vit?? I get it that they are pretty good-- I have some 540 and 550 on the shelf. I'd go to rl25, rl33, or retumbo though with the 7stw. Heck of a lot cheaper powder that will do as well or better than the Vit.
Sorry I cant help with any loads as I only shoot a 7mm WSM. I was wondering if any of you shooting these 180s at very high velocities have had them start to blow apart from high rotational speeds? If so, what sort of speed and twist rate did they start to blow apart at?