ORIGINAL: turkey harvester
I use the same gun but without a full dip. It has a 22 inch barrel and I got a .640 hastings choke in it. I shoot #6 3 inch winchester supremes with it. I can kill one out to 50 yards easy. I love it for the price. paid $239 for it. Shoots just as good as the big name turkey guns.
Im not sure of the concept behind the choke you mentioned... I know improved, mod, full, x full, but what is a .640? Is that smaller than the Extra full that comes with the gun?