I don't know what happened to my reply to Duff but here it is again: You're surely welcome to respectfully disagree with me on this or any other subject. However, my experience in lengthening forcing cones on several of my own guns showed no reduction in recoil. Whether it changes your patterns or not is another story but brings up the question of do you need different patterning? The fact is that recoil has nothing to do with the shape or length of forcing cones, bore ID or any other mythical crap promoted by the barrel jockeys. Recoil is determined by the weight and velocity of the ejecta and the gun weight.
About 40 years ago, when this barrel magic was just beginning to show up as an expensive solution to a nonexistent problem, the American Rifleman's expert staff stated that "nothing you can do to the inside of the shotgun barrel will reduce recoil unless it reduces velocity". That was true then and true today. Believe what you want.
jl
