RE: Anyone use BP in modern cartridges?
Basically with black powder in straight wall cases you just fill to the top and leave enought space for the bullet. A little compression is OK or drop the powder from about 24 inches through a drop tube to settle it. With black powder you do not want any air space. Black powder is not a good idea in any bottle neck cartridges however. If you want less powder you will have to fill the space with cream of wheat or similar filler. Your pistol will easily handle any loads you can stuff into the case using black powder.