The VihtaVuori pistol powders are single base, porous powders that also meter well through most powder measures. The burn rate of this powder is slower than N320, and similar to Alliant Unique. Especially well-suited for 9mm Luger, it also loads well in .38 Special, .40 S&W, .44 S&W Special, and .45 Long Colt.
Big Book Catalog, Issue:67, Page:527
Sinclair, Issue:4B, Page:094