I have M11 Sportsman in 20 gauge with a solid rib fitted with an aftermarket Cutts compensator.  Very popular post war bird & skeet gun in the south.  This gun configuration was very popular with the WW2 vets I grew up around because they trained with them, I believe.

I bought one of those after the North Hollywood bank robbery were the robbers were wearing bulletproof protective gear including helmets and gloves and the police went to B&B Sales in Burbank to get the M16 variant, that caused Police Department to drop the S&W 38 Special 6 shot double action revolver and adopt the 357s or the 40 or45 caliber semi automatic handguns. The one I bought had an 18 inch barrel and was 12 gauge and had a 2 3/4 inch chamber only. The 2 3/4 inch chamber essentially making the 3 inch and 31/2 inch shotgun ammo with the steel shot for Waterfowl unless. But I do have boxes of 2 3/4 inch Buckshot lead in 4s , 2s and double sized to 36 caliber.

I have a 16 guage ("the sportsman" stamped on the bolt), with the poly choke and holds 4. No game scene rolled stampings. Date code puts it in service April 1934. Got it from my dad.

Super helpful but you can't run steel loads through it?

Mine doesn’t have any weights but it has a reversible split ring.. one  way for heavier loads and reverse for lighter loads. Never heard of any weights

Definitely not a good home defense gun, if you need to reload under stress you have to press the button on the receiver to stuff a shell in the magazine. With modern shotguns you have more capacity and just stuff in the shells.