Vihtavuori N170 is the slowest burning rifle powder in the N100 series (not taking 20N29 and 24N41 into account) and in fact one of the slowest canister-grade powders readily available from any manufacturer on the market. As with all of our rifle powders, N170 grains are of the cylindrical, single-perforated extruded type. With a length of 1,7 mm and a diameter of 1,1 mm, the grain size is relatively large.