I have a question. My primary gun for shotgun season is a H&R ultra slug hunter. I would like my backup to be my remington 870 just in case I needed to use something other than my primary gun. The 870 has a bird barrel. Can I shoot rifled slugs out of the bird barrel? What choke is reccommended if I was to do this? Any help is greatly appreciated.

Improved, or a modified choke usually does well with rifled sugs.