28 December 2019
Maybe not exactly what you are looking for but there is a website that has a forum where the shooters only use cast bullets. These bullets are plain base, either GG (grease groove) or PP (paper patched). Shooters use either BP (black powder) or smokeless powder.
There are two manufacturers of replica older style Sharps Model 74 or 77 BPCR (black powder cartridge rifles) and a few other types, ocated in Montana; C. Sharps Arms and Shiloh Sharps. This forum is sponsored by the Shiloh company. There are a lot of topics that are discussed including bullet alloy, lube, bullet sizing, powder selection, etc.
If your rifle of choice is a Sharps, Win. High or Low wall, Remington Rolling Block, Hepburn, etc. you may find this site interesting.