You can indeed make chokes shoot tighter or looser patterns, and that's without stuff like spreaders. Don Zutz was a big fan of mod, because he realized it could shoot patterns ranging from IC to close to full depending on shell selection. Take a load of small shot with a cork or fiber wad, compare it to a load of larger shot, with a plastic shot cup. Maybe toss in buffering. You'll get some significant variations in pattern.
But McIntosh's point--although he didn't go into great detail--is that you can also make cylinder shoot IC or tighter patterns if you feed it the right ammo. But it retains the advantage of being able to throw true cylinder patterns without resorting to spreader loads. And per Mr. Brister--a fair hand at both game and clay shooting: "I do know that at 25 yards a pure-cylinder barrel will throw one of the deadliest game-getting patterns you ever looked at, more efficient at that yardage than a full-choke barrel at 50 yards." He also pointed out that Oberfell and Thompson found that cylinder patterns tended to be more even than those from guns with choke. When you add to that the fact that in some types of upland hunting, 25 yards is an unusually long shot--certainly true of grouse and woodcock!--the value of cylinder becomes even more apparent. It's obviously not the choice for guys who are shooting 50 yard clay targets . . . but then only a tiny % of upland hunters can hit 50 yard birds. And based on my own experience--using 3/4 ounce loads in a 20ga--you don't need any choke at all to break skeet targets consistently.
