For most people the best route for a a vise is the buy a milling machine vice from some place like Harbor Freight etc. Even MSC has cheap import vises. Smooth sharp edged jaws and they also work great for making rod pipes and other brass bending chores .
The only jaw pads needed for pulling breech plugs is a sheet of heavy paper.
Just don't crush the barrel. A lot of torque is not needed with the flat jaws and paper pads.
I have a 4" I am going to mount on a pedestal so its possible the work on all sides of it.
Dan
