Even the .22 Hornet cartridge could easily be reverse engineered back into the black powder .22 Winchester Centerfire that it was developed from. The .22 WCF shot a .228 diameter bullet but I suspect the .224 bullets that modern .22Hornet rifles were designed for would work just fine.
Back in the '70s, I obtained a can of black powder before I even owned a muzzle loading rifle. My first black powder experiment was loading a 12 gauge shotshell with black powder. Not having any loading info for black powder, I simply looked up how many grains 3 drams amounted to and weighed out that charge on a scale. It went boom, the critter I aimed at died, and I was surprised at the huge cloud of smoke that obscured the target after the shot.
Later, I loaded up some .44 Magnum rounds with a case full of black powder. They shot, were surprisingly accurate, and very pleasant to shoot, like a .44 special, which I believe was originally a black powder round. Not knowing any better, I used the same jacketed hollow point bullets that I used for smokeless powder loads, but they worked just fine.