BPI-often mentioned here-both as a resource and a purveyor of supplies and tools offers a free catalog. Mine came recently and with 14 pages of detailed data on wads it has dissipated the mistique of how does one wad compare to another. Now if only I could find similar detail for shotgun powders. Reading the manufacturers description, they are all the best thing since sliced bread. My Lyman Shotshell Manual, 2d Ed. is somewhat dated in that regard.