The chambers are opened up to the rim diameter then the new tubes are turned to suit.When the rims are re-cut it will just clean off the end of the sleeve.
I will take this opportunity to say to people that I dont think that welded sleeving is a good idea.In days gone by when the sleeve was tinned in,the full surface area of the join was attached to the remaining breech end.This effectively makes the area from the chamber to the outside of the breech end one piece.With the welded sleeving the join is only joined at the two welds(Two if the rim has been welded in aswell).This effectively leaves a gap between the sleeve and the remains of the original breech which is unsupported.It means that the join is much weaker than a fully tinned join and if a weld fails the tube could come out.
