Admittedly, the barrels I have bent to regulate, were all old shotgun barrels from Dixie, supposedly made in the 1880's, and were relatively thin wall thickness, compared to some modern barrels. As was mentioned, any major wall thickness change ( wedding rings, dove tails, ect. ) is going to be a problems, if you're not careful. We found that a small hydraulic bottle jack, with a home made adapter to fit a bending head off of an EMT conduit bender, worked better than anything. It spreads out the pressure as you proceed and helps to eliminate kinked barrels. Pushing from below eliminated the issue of running out of space, for the major over bending required. We nailed a 4x4 cripple to the 4x4 center leg of the work bench, to mount the jack. we then cut a hole through the bench top, to allow the jacks piston to fit through. A short piece of heavy wall pipe with threads to fit the bender head, and some creative welding on of another size pipe to fit the jacks ram, along with some home made tall V blocks with ears to accept U bolts, and we thought we were ready. If your bench isn't built like a tank don't try this method. Ours was planked in 2x10 pine and we still pushed it apart. The fix was a steel backing plates below the V blocks on the bottom side of the bench top, held in place by the U bolt that secured the barrel ends. Once we got it built, it worked amazingly well, and even allows you to put a scale behind the barrel to judge the spring back.
Hungry Horse
