There's a bunch of posts on the Rimfire section of the Cast Boolits site where people load and reload rimfire cartridges.

Haven't tried the primer mixture but I ordered 1000 primed .22RF cases from FedArm and now&then try some black powder loads in one of my more easily-cleaned .22s.  So far the results are nothing that will make the Board of Directors of Eley's, Ltd. lose any sleep over, but it's interesting; to me, anyway.

N.B.:  A Stevens 44 or Tip-Up design is much preferable to more elaborate actions for this kind of work.  That blackpowder smoke gets into the breechblock plunger cavity in a Stevens 44-1/2, necessitating almost complete disassembly.  A 44 you just have to wipe the breechblock face and the outside and clean the barrel.  You have to take the block out of the action to clean a Ballard or Winchester (or 44-1/2) breech face.

I'e saved all my fired Navy Arms .32 Long and CIL .25 rimfire cases against the possibility of reloading them sometime.  I'll be interested in reading your results.

I would buy a few cases. Thinking it would sell very well here.

I assumed it was corrosive. The non corrosive is much harder to make.