By my reading of the old catalogs it seems the comments about Ballard rifling, if parsed out, only vaguely applied to the 38-55 'Target Model'. In fact, it is not really said that it is Ballard rifling, only a reference made to the Ballard and the H&R having 'original style' rifling. after the 38-55 was dropped, even that reference disappeared.
Even so, the 45-70's typically shoot cast and jacketed bullets very well, and much rifling depth on modern guns is .002 -.003 deep. The 'old, deep' rifling of the muzzleloading and early cartridge guns is long gone.