.458 bulging Starline

[laowho]

That's the long and the short of it. Itsa Shiloh 45-70 and reports that it's a consistent .450-.457 seem spot on. Tight chamber as expected. Loading the .458 bullets which measure true are bulging the S'line brass noticeably and such that they won't chamber. Undesirable option would be to size bullets to .457. Am hoping that the Rem. brass, with thinner walls, will load the .458 bullet w/o bulging the brass. Anyone have the same experience? Guess I should just try some? Thanks, Doug