I'm new to reloading. Am starting with 9mm Luger ammo. I have a Lee powder measuring device. It appears that powder is available in several forms, (1) circular flakes or wafers, (2) small cylinders and (3) small spheres or flattened spheres. Since some of these forms might plug up the measuring cylinders, some care probably should be taken when selecting a powder, especially since the individual powder load can be pretty small. Trouble is, this type of form information doesn't seem to readily available and I think I should probably be looking for spherical powders. Does anyone know of reference material or a web based source that describes the powders available on the market by their basic type, regardless of manufacturer? Thanks for your help.