RE: What would you recommend i do??
On my Waterfowling shot gun, I have 28" barrel and I think it is the industry standard for fowling. The only guys that I have ever seen use shorter barrels were hunting a goose field and they would shot at about 15 to 20 yards. I would not mess with the chock tubs with a 21” barrel, you will need a longer barrel, unless all your shots are right in your grill.