Well there are two ways you can go.
For a shotgun, you can buy a facing cutter for $75 bucks.
Or, you can file square using a machinists square and a $5.00 fine cut file.
Then rub the sharp edges left from squaring it with the file off with some emory paper on your finger.
Same with rifles.
You say you have 'a few barrels' to crown?
About the same cost for a cutter & pilot for each caliber.
Or, the same square & file you used on the shotgun.
And a big round-head brass screw from the hardware store.
And a can of valve grinding compound from NAPA auto parts store.
Put the screw in the drill and lap the sharp edge off the inside of the rifle muzzles with the brass bolt & grinding compound.
For about $15 bucks.
rc
