I believe the poster above who mentioned the High Standard, having the screwed in barrel, hit on something very important to smoothbore sluggers.
The barrel/receiver joint on most shotguns is just a slip fit, but several shotguns were made with fully threaded or interrupted (partially) threaded barrel to receiver joints.
some of those shotguns were:
Win. model 12 (interrupted thread w/ tensioning mechanism)
Ithaca 37 (interrupted thread)
Savage 67
J.C. Higgins M20 (High Standard Flite King)
In addition, the Smith and Wesson 916A (Nobles pump), and the Winchester 25 (non-takedown model 12) used fixed barrel to receiver unions. These guns should make superb sluggers.
A red dot sight on such shotguns can make the 100 yard smoothbore slug shot a consistent slam dunk. Many of these guns are old "house brand" chain store shotguns and a little modification won't hurt their values.
Then you have the many bolt action shotguns that were commonly in use years ago...most have fixed barrel to receiver joints, many have adjustable chokes which after a little experimentation will allow accurate slugging and tight buckshot patterns to boot. They typically just need a good set of sights....most will accept a sidemount for a scope.
I have often wanted to try building a smoothbore slugger out of one of the old 98 Mauser actioned "GEHA" shotgun conversions that were made in Germany years ago. One in good shape with a good bedding job and/or a freefloating barrel, and a good set of sights ought to be the apogee of the smoothbore slugger.
