I agree with Gunut and Laxcoach. Recoil is the limiting factor with vintage double guns. L Cs are particularly weak in the stock head due to the amount of wood that must be removed to accommodate the locks. I would limit loads to 1 1/8th ounce of shot at 1200 fps velocity (good trap load) to stay in the 19 to 21 ft pounds of recoil range to be on the safe side.