I have 2 bolt shotguns 185 KA and 385 KB.
There are no "optional" bbls. Unless yours has been cut,
they are all about 25" with the C-lect choke.
If it is short, you might want a "new" used bbl but they are
not easy to find. Probably easier to find another 185 and strip it.
All in - it is at best a $100 gun- but they do shoot well.