VV is available (as much as any powders are available) pretty much anywhere. For the price check I went to Midway. VV is Finnish and a part of the Nammo group that includes Lapua and Berger. Flow is lately determined by granule shape and will vary with burn rate and composition. N555 has a uniform, squat, square cylinder shape that meters very consistently with my Lee Perfect powder measure. It uses wipers. I’ve been throwing charges well within half a grain.