What choke and shell are you using? To many guys are using the wrong choke in their guns. Somebody says super full is the only way to go and you buy in. Go pattern your gun and try a lot of different shells and shot sizes and pay loads and chokes. My poor old Win. 1300 won't pattern with anything over 1 1/4oz of shot. It shoots 5 or 4 shot the best, but only at 1200ft/sec. And with a full choke, anything tighter kills my pattern at 40yds. The new guns with lengthened forcing cones and overbored barrels are nice, but since I put the time in I can kill the same bird at 40yds they can.
Gselkhunter
I was using a remington super full. Hard to pay a bunch of money for every choke under the sun. I used remington #6 last year. Looking into others this year.
So Mr. Long your the only one that has positive response to lengthened the cone. I was doing this on a 870 express barrel. So I am sure its short cone.