Sharps,
Understand that this is a completely uneducated opinion,since I have exactly zero experience loading shotgun shells,much less "Punkin Ball" loads. The area of interference with the RB you would be pretty small( I guess we could calculate it, but that would really be too much sugar for a dime)and since the ball would be moving when it hit,I don't think the pressure would spike much. In my experience,my inside measurements with a caliper directly comes out smaller by a couple thousanths than if I use a small hole or T gauge and Micrometer.This would give a little relief.Its pretty well known that different alloy will give different bullet weight, but it will also give different diameters.You might lose another couple thousanths by varying the alloy, here we go again with that sugar.The performance with shot seems good enough that I would recommend just using shot, except now you have me interested in what a ball will do.
Mike
