I haven't noticed scoring in any of my older guns, but if that is a concern, don't do it. The late Kenny Morgan killed a bunch of birds with his double .410 and he shot both barrels at once by pulling the front trigger with a cork between the triggers. If it's a 3", there are lead loads of 3/4" oz in 7.5". Shoot the distance where you get 80-100 pellets in a 10" circle. That's your limit of range for a hitting something vital in the head and neck. I don't recommend firing both barrels at once. You've got old wood in that gun that might have a problem with 1.5 oz. shot at once with the resulting recoil. Gil