Gents:
Greetings from Alaska.
My 4-bore Hughes is a cartridge gun and can be seen on my website. It is a 5-bore in bore size (as are most) at .975" diameter. I use Blue Dot as my smokeless load as FFg GOEX. Don't bother with with Fg as it burns too slow and dirty. 10 drams of FFg is a stiff kicking load in my 22 pound double and 16 drams is down-right unbearable with nearly 1500 fps with a 1743-grain conical bullet. I don't know about patches or muzzle loading rifles but I do have a bit of experience on bore rifles and nitro rifles in the cartridge era. Many rifles can be seen on my website. Take a look.
Cal