A major consideration here is the distance from the cylinder face to the recoil shield or face (don't know the exact terminology.)

One of the reasons Freedom Arms counter bores the cylinder is to be able to decrease this distance and hence tightens up the cylinder opening, making a tighter and cleaner looking revolver as there is hardly any space showing there.

Try counter boring a standard Ruger cylinder without further mods and you will create a big problem of headspace.