Well, you can get 21 Sharp at MIdway for $19 per 100 rounds, or Winchester 22LR for $9 per 100 rds. Granted this is "plinking", target and small game ammo, but still one third the cost. On paper, the 21 Sharp may look better, but in the real world, I don't personally see it making much of a difference. For some reason my thoughts keep going back to some of the 17 rimfire cartridges and especially the 5mm Remington. I have to also think back to other new cartridges such as the 338 Federal, all the WSM line, 9mm Federal, 307 and 356 Winchester, and many others that were touted as a "wonder" caliber, but soon faded into oblivion. Ruger might chamber the SS in it, but I would bet it will be a small flash in the pan offereing.