12 guage with rifled barrel...any problem shooting 00 buck? I'm guessing the wadding cup means there is no problem for the barrel, but may mean the shot pattern is near worthless? BUT, figured I'd ask some shotgunners...and if using shot, does it matter what kind (tungsten, etc?) with rifled barrel? And, another dumb question I guess..what's difference in a rifled barrel and a deer barrel, if any?