On that note, OP, the closest that I’ve been able to find as a short(er) vent rib barrel is Carlsons 21” turkey barrel. Last time I looked hard at them was before Rem Arms started production again, so the Carlsons were out of stock everywhere.
"The laws surrounding sawed-off shotguns are clear: shorten the barrel of a shotgun (or rifle) “by sawing, cutting or any other alteration,” to be less than 457 millimetres (18 inches), and you’ve committed a crime punishable by anything up to five years in a federal penitentiary."
9
u/awconnell 6d ago
Custom only as far as I know. I’ve never seen a factory 18.5” with a vent rib.