I agree with the IC being great for most shotgunning.. It or an mod. are about as tight as I want in a shotgun except for gobblers.. As for shooting squirrel, I had friends in W. Va. that used to do a lot of tree squirrel hunting before their country was developed for big city interests.. They felt squirrel shotguns should be full choke due to the small size of the animal and tough hide.. They felt a squirrel could soak up more shot for its size than a rabbit or grouse..
Your friends were absolutely right. Tree squirrels are ALOT tougher than rabbits or grouse. I've killed several thousand squirrels over the years with 12,16,20 gauge and .410 shotguns. Full choked guns aren't really neccesary in 20 gauge or larger guns unless the timber is unusually tall in your locale. Modified works pretty well out to 35-40 yards so long as you're shooting at least 1 oz. of 5's or 6's. Improved cylinder sucks for squirrels in tall timber. So much so that you'll be seriously handicapping yourself with it. We have 80' + tall hickories around here and 1 - 1 1/8 oz of sixes through an IC choke won't consistently provide clean kills on squirrels feeding in the tops, even if you're shooting straight up from the bottom.
