Welcome to the Forum. Black powder is loaded by volume and any cartridge loading must NOT contain any air space. When loading a black powder round, you need to determine how far the bullet you intend to use will be seated in the case. Once that measurement is determined, subtract 1/16" and that dimension is the line in which to fill the case with black powder. BP should be slightly compressed and the 1/16" will accomplish that. Once you do this, you can measure the volume of powder in the case and repeat the loading by a powder volume measure.
Not sure why you want to do this, but I would use 3F and a 158 grain lead bullet.
SWCA 2515 Grip is a verb