Lol, it' s too late for that now.

You can shoot rifled slugs in a rifled barrel. What' s that worst that you have? A 12ga lead slug shooting in a 12ga steel open choke barrel. It does junk it up, but that don' t mean you can' t clean it. If rifled slugs were all I was ever going to shoot in it there may be a problem somewhere down the line.

Why would I plink with a slug gun? Why not? You have to get used to it sometime.