the only rifle I know this was made in a great amount was the french chassepot needle fire rifle

this model was rebuild for metallic cartridges in the 1870s in germany for the 11,15x60R mauser

and france for the 11x59R gras

11 mm Mauser, Gras and Chassepot

they drill out the old chamber and make an insert with a slot so it could not move. the barrel was screw into the receiver again and the insert was bomb proof. then an new chamber for the metallic cartridge was cut.
dont find a pic showing this but a similar insert in a Mauser 71 barrel so you can see how much material was around the chamber insert.

this works with a 25 gramm lead bullet and 5 -5,25 gramm black powder