Ken:
I’ll echo the comments of many here already, especially regarding the 10″ circle at 40 yards bit. This has always been my gauge for success with a load. Anywhere in the 100 mark and you’re good to 40 in almost any conditions. 150+ and you’ve likely got yourself a 50 yard gun, though make sure to pattern first to check it out. Also, before considering anything past 40, make sure you’re using 4 or 5 lead, or preferably, 4, 5, 6 or 7 Hevi-type load.
The denser-than-lead loads have gained incredible popularity because they hit harder downrange, and typically pattern much better than even the hardest copperplated and heavily buffered loads. Each mfr. has their own name to it, Winchester Xtended, Hevishot, Federal Heavyweights, etc. I’ve shot the Winchester xtended and Hevishot mag. blend the past two years and loved it. I typically see patterns in the 150+ range with my gun.
If you stay with lead, I’d check out the tighter constricted choke you mentioned. If you move to one of the hevi-type varieties, I’d stick with the choke you have.
Of course, all of this is much ado about nothing if you just pattern your gun like you have, and stay inside your max effective range at all times when shooting. Alot of turkeys were killed with single shot fixed full choke shotguns and blue overalls.
You’re going to love that Camp Ripley hunt. Loads of birds, and lots of room to roam. Congrats on doing what it takes now to have a successful hunt then, and good luck!
Joel