Let's say you have an old drilling and you need to make a casting to determine the cartridge size. Where do you go from there? The only books with specifications I know of are for nitro cartridges. Did any of the black powder cartridges have shoulders on them? Measuring shoulder angle and length off a wax casting looks pretty difficult. There are black powder cartridges that became nitro cartridges. Knowing which to use must be difficult. More info please. Thanks