Not all repairs done in the shop requires machinery or special know how. Sometimes it can be a quick fix. This old Colt revolver came in because the barrel had been cut down, but it needed a new crown on the muzzle.
A crown is basically a type of finish at the muzzle so the bullet can break free consistently. If there's any uneven edges, the bullet might release from the barrel in a different way from the previous shot, causing a loss of accuracy.
Ordinarily, I would pull the barrel from the frame and turn the crown on the lathe. But as short as this one is, and considering the age of the gun, a quick fix was to bevel the inside edge of the barrel to get the rifling to release the bullet with more consistency. There's no burr to hang up and cause gasses to flow around the base of the projectile unevenly.
Another handy little tool for the outside edge is sold by Brownells. This smoothly cuts the outside burrs of the barrel and doesn't leave anything to snag your skin on. You simply chuck it in a drill and smooth the outer part of the barrel.
In just a few minutes, you have a small crown on your muzzle and it'll increase the accuracy of your gun. A bit of cold blue to touch it up, and you're back in business.