I have been having trouble getting consistent SD's and found that my auto-powder thrower was .1 grain variance or worse so I started double weighing. Started wondering what difference one kernel of powder makes on a 40+ grain load to velocity. An average kernel of powder of 4350 weighs about .02 grains. Do these extremely small variations really have much of an influence on velocity? Recently watched a video of Scott Satterley getting extreme spreads of 2fps. Amazing.