Back in the day, when we could shoot waterfowl with lead shot, I suspect fixed choke shotguns were more common - they did not have "interchangeable" chokes. My Browning Pump Shotgun in those days had a "fixed" Modified choke. Our son now has that gun. A "choke" is a constriction from the main bore size - unless the barrel is stamped "C" or Cylinder, there will be a "choke" - either fixed or threaded for one. Look into the muzzle - if there are fine threads inside the barrel, you DO NOT want to fire that without an interchangeable choke in place - there are several kinds - not all are interchangeable, one brand to another - I believe the thread pitch or the placement of the threads are different. If the barrel is smooth inside - no threads visible inside the bore, then it is likely a "fixed choke" and the barrel will likely be stamped or lettered as such. Of the current Browning Pump Shotguns here - a 12 gauge and a 28 gauge, have changeable chokes. The Browning Pump Shotgun in 20 gauge and a Winchester Model 12 in 12 gauge have fixed chokes. A Browning Cynergy, in 28 gauge, has both barrels threaded for replaceable chokes. I do not own, and have never owned, a semi-auto shotgun . Another guy has left a broken Weatherby SA-08 here to fix - it is chambered for 12 gauge and has a replaceable choke screwed into the muzzle - that one is a semi-auto. In the old days, was very common to use a fixed full choke for shooting geese - if you shoot those guns with steel shot, as required these days, that will likely crack (split) that barrel or blow off the end - is most common to see recommendations that fixed choke barrels of fixed Modified Choke or more open choke will tolerate being fired with steel shot. And, of course, that crack or blow-off may occur on the next shot fired, or 30 shots from now - no way to tell, as far as I know. Is possible that a previous owner may have lost or misplaced the choke set that would have come with that shotgun, if it had replaceable chokes - or it might be a fixed choke barrel? I understand some older shotguns were made with walls thick enough to be reamed out and then tapped for changeable chokes, and I think the company "Briley" sells "thin wall" chokes, as well.
