A charge of 13grns (weighed) of Hodgdon 777 with a lubricated wad and a .457 swaged rather than a cast ball also works for me. I find the Old Army a bit too heavy to shoot with a one hand precision stance, but do quite well with a two handed hold. Even though this might be considered a light load, it provides enough recoil and noise while still being comfortable to shoot.
https://imgur.com/WooJXhf
Brian