I also own a Remington 870 Super Mag. After a exhaustive four-year search, I found that the Remington Super Full Turkey Choke delivers the deadliest pattern I have ever seen. That was after using the HS Strut "Undertaker," a Remington Extra Full, and one other choke.

The Super Full delivered about 40 pellets inside a 10-inch circle at about 30 yards. The beauty of this choke is that distance is an ADVANTAGE, not a disadvantage. You aren't disadvantaged until the bird gets CLOSE because of the tight pattern. This choke simply slam dunks turkeys. Best shot is either a 3" #5 or #6. Deadly.