The current factory production 357 and 44mags have an SB1 frame, but the only rifle barrel(s) that can be used on them are the barrel(s) that come with them, whether it's the single firearm or one of the combos with shotgun barrel, they post a warning to that affect on the website and in the catalog. For any other application, SB1 frames are for shotgun/muzzleloader barrels only with the exception of the 45/410 barrel which can be fitted to SB1 frames and comes that way on the production 45/410 Survivor.
Tim
