FWIW, shotgun beads go all the way through on thin smoothbores.
That said, I would rather not have to clean up burrs into a bore, especially rifled, though it can be done. The steel ramps can be soft soldered or even epoxied on the barrel exterior ('silver' solder is not required). I even used black electricians tape to tight wrap a ramp on one barrel to try it out and it was on for a season. Something like that lets you use the bits you think will work, and postion them to try before you 'get serious'.
