As much fun as a .38 or .357 is when shooting plinker loads in a rifle, if searching for a .22 substitute those cartridges miss the point. Consumption of three times the powder and three times the amount of lead per shot is not a substitute (save perhaps in terms of the fun quotient). The closest we can get to Dan's request for a solution, in a current factory cartridge, is the .22 Hornet shooting home cast bullets over a pinch of pistol powder. Replacing cast bullets with jacketed stuff or store bought cast stuff in the Hornet defeats the purpose by increasing costs dramatically (relatively speaking).
By doing everything yourself (casting, loading, etc.), using scrounged lead that is free or virtually so, one can equal or beat the cost of average .22RF ammo-- the wrench in the works is the time spent doing it. If one views that as a hobby and treats it as one would any other handloading venture/experiment in chasing pure accuracy it makes total sense. If one's goal is to prepare plinking ammo for blasting tin cans, golf balls, rocks, and pine cones at 50 feet (wherein I bet 70% of RF ammo gets wasted in this country) then it's a losing proposition- save your time and buy a brick of Walmart .22's.
