Oldtimers used to bend their barrel in the fork of a tree. Since I do not have a real gunsmiths barrel bending jig (yes there is such a thing) what I have worked out is as follows. I cut 2 pieces of 2x4 appx. 6" long, I wanted to end up with a half circle appx. the diameter of the barrel I am working on one one side of each piece. For a Handi 12 gauge I made them by drilling a 1" hole in the center of 2 pieces of 2x4. I then cut those pieces in half right through the center of the holes so I had 4 pieces, each 6" long by 2" wide (appx) and each has a half circle cutout in the middle of one side, those cut out half circles are the bearing surfaces that contact the barrel. I used 3 pieces to bend the barrel. I set up the barrel in the opening of my fireplace, a good solid brick and mortar opening that will not flex or move. I set the barrel in the frame with a hydraulic bottle jack with one piece of wood in the bottom center of the barrel (to lower point of impact), jack up the barrel until there is just enough room to place another piece of wood over the top of the chamber and the top of the barrel as near the muzzle that you can get. Pump the bottle jack until there is some pressure on the barrel, then slowly add pressure until the barrel bends ONLY A BIT!!. Take it to the range and shoot for effect, you most likely have not bent it enough but as in all metal work and gun work take it slow and easy. It sometimes helps to have an extra set of hands, my wife does not like to see when I do it but she's a great help (
)...best of luck....<><....
P.S. - if your bottle jack is not long enough to reach out and bend the barrel you mau have to use a piece of 4"x4" about a foot or 15" long on the top of the bottle jack ram, cut the 4x4 to length for your particular needs, other things would work as well, 2 2x4's nailed together for instance. This is where the extra set of hands come in handy, to hold the 4x4 straight and to slowly pump the jack handle until contact is made, then adjust for straightness and pump it up....<><....