Ruger mk1 problem

[M1NM]

use a 1/4" drive socket and extention. Ream it lightly by hand you don't want to cut it any deeper. When you changed the extractor did you clean out the slot and spring hole? Sometimes they get dirt in them and don't let the extractor fully engage the cartridge rim.

[Bainter1212]

My reamer screws onto the end of a cleaning rod. You put the cleaning rod through the barrel from the muzzle end and then screw on the reamer.