The 225 Winchester really doesn't have a "parent" case. It is very close in dimension to a .30-30, but with a slightly smaller rim diameter of .473" vs. .502" The .225 can be easily made from .30-30 by trimming the rims, and necking the .30-30- to .22 caliber, and shortening.
Rims can be trimmed in a drill press, or even a 1/2" drill motor, by chucking the case lightly, and applying a file to the rim to take off the .029" dia.
Hope this helps.