I've never done it personally. But everything I have heard, read, etc has said do NOT shoot rifled slugs out of a rifled barrel. The main reasons i've heard are the amount of deposits the lead leaves in the grooves is next to impossible to get out, and that the large rifled slugs can wear out the rifling. The only thing I question about this, is that rifles shoot lead or copper plated lead, so what is the difference? Again, I don't have any personal experience with this, thats just what I have been informed. By the way, why would you want to shoot those pumpkin balls out of a rifled barrel anyhow?

--Man who fish in other man's well often catch crabs--