The third bite on a shotgun is just like the third barrel lug on a 98 mauser. It holds nothing unless something else fails. As far as the action goes the unless you have the metal tested it would be hard to determine the strength of the steel. Have you dismantled your action. Chances are that your firing pins are integral to your hammers witch presents a problem in itself. Recoil is subjective but your stock is not. If your using your old stock it may not stand the strain. I broke the last one that I am building and am now repairing it.