As we all know as casters bullet dia. can vary & that can mean a wonderfull feeling of succes or a leaded barrel from chamber to muzzle !!!
I have molds aluminum & steel that cast undersized wit stik on WW then .002" over with WW with a touch of linotype , even temp & casting speed has an affect on dia . but the biggest effect is alloys!
I`ve found the older Lymans cast "fat" up to .004" over on the older IDEALs & some very early Lymans .
If I was looking for a specific dia out of a certain alloy i`d look up a custom mold maker in a minute , some over on castboolits.com offer truely custom designs at a very affordable price !!