If you want a 22 calibre that used to a wildcat, you can buy 22-250 factory ammo. Otherwise anything that involves a big crazy necking down, is going to have to be done yourself. Number 1, there's not the demand, Number 2, the companies learned a long time ago with the original loadings of 220 swift and 250-3000, that people get mad when the guns they buy and use factory ammo in, get burnt out in 1000 rounds.