If the shotgun is rifled then there is no choke but if it is smoothbore then an improved cylinder is the "standard" for a slug gun.
I have a Mossberg 500 sluggun and it is an improved cylinder bore. It does not have a screwin choke and the barrel is 22" or 24" (I can't remember) tapped for a scope and no bead.

The foster slugs like the Rem and Winchester are designed for this type of barrel.
Good Luck!


Greg

"Getting close to the game is the joy of Bowhunting for me, the harvest is a bonus."

Live 15 ft Python after eating a small Antelope!