VihtaVuori is a Finnish Powder Company that has been manufacturing powder since the 1920's. VihtaVuori powders are extremely popular with benchrest shooters, High Power shooters, and varmint hunters.
A very slow burning magnum propellant for use with heavy bullets. Applications begin with very heavy bullets in the 30-06, and include the 338 Win. Mag.
Big Book Catalog, Issue:68, Page:544
Sinclair, Issue:5B, Page:094