NY,

Switch to a modified or better yet an IC choke. If you don't have them, Buy some Brenneke slugs, they are more forgiving in tight chokes. I shoot the same winchesters out of 3 separate guns that are Improved Cylinder, and get excellent accuracy. For $3.50, it might be worth it to try the remington sluggers also. They seemed to shoot well through a skeet chokeI had on my 20 guage.

KEJ