FACING or CHAMFERING the MUZZLE
After shortening the barrel it is necessary to finish the end of the barrel. This is "facing" or most of the time "chamfering". The idea is to finish the end of the barrel so it is perfectly symmetrical with the bore, and at the same time have the rifling extend to the end. Most of the time this takes the form of a recess, or "dished in" area at the end of the barrel. This recessing makes the rifling much harder to damage during normal handling. I will show two ways of doing this, one rather expensive, one rather cheap, and a third that you should NEVER use.
These are the tools used to chamfer the muzzle. Above the red line is a Brownells chamfering tool with pilot and four additional pilots. The tool and one pilot costs $65 and additional pilots cost $18 each. The Brownells system works very well, as is true of all the items sold by Brownells, but with Turks selling for $40 it seems a shame to spend $65 to finish the end of a barrel. Here is a link that shows the Brownell method very well, The LINK.
Below the red lines, to the left, is a can of 400 grit Clover grinding paste, a 5/16-inch stove or carriage bolt and a 3/4 or 1-inch mounted stone costing $1.25. You could possibly substitute valve-grinding compound for the 400-grit paste. (Get the 400-grit stuff, you can use it to lap the locking lugs and "jewel" the bolt.)
With the barrel held in a vise, push a cleaning patch from the chamber end until it is about 1/4-inch from the muzzle. With the mounted stone in a hand held drill, begin to "drill" into the end of the barrel.
Rock the drill motor from side to side and up and down while removing metal.
When it looks like this, stop. This took about 4 minutes, including the picture. Note the grinding marks left by the stone.
Now place the stove bolt in the drill and place a dab of grinding compound on the head.
Run the drill motor and add compound until the muzzle looks like -
this. Some grinding marks remain, so go ahead and use the bolt/compound until you are satisfied. Push the patch forward and it will remove the grinding compound that has entered the bore. THROW THE PATCH AWAY. Run another oil soaked patch from the breech thru the barrel to remove all traces of grinding compound.
You could just use the bolt and compound, without using the mounted stone, it would just take longer.
Round the outer edge of the barrel to suit with fine sandpaper.
NEVER NEVER NEVER NEVER NEVER NEVER NEVER NEVER NEVER NEVER
NEVER try to do this. The grinding compound will get on the shank of the screw and destroy the rifling.
NEVER NEVER NEVER NEVER NEVER NEVER NEVER NEVER NEVER NEVER NEVER