Since the pressures are so much less in a shotgun than a rifle, the recoil is only reduced about 10-15% verses 30-50% in a rifle. Therfore the noise is not increased to much either. However the muzzle rise should be decreased significantly. At least based on all the info I've gotten over the years, and having a muzzle break on one of my rifles personally. I've thought it about my self for my slug gun, except for the maintenance factor of snow, rain, dirt and deb re. It's just one more potential problem to have out in the field, and it just doen't seem that the benefit is that great that I personally would want to risk more issues when I hunt.
As far as your question about the forcing cone, I just replied to a post on this forum titled Tar-Hunt guns. If I were you I would contact that gun smith, Dr-Mar, they length end my forcing cone and did some other work that made my slug gun incredibly accurate. The forcing cone is only one thing that causes slug guns to be inaccurate. Barrel slop, poor crown, heavy trigger, and the wrong slugs for your twist, can make you go out of your mind at the range. I wish I would have found these guys sooner, would have saved a lot of money.
