Magnumdood, you are correct.
With a .72 bore there is much over-choke effect going on. As I stated in earlier in a post, there is more to it than just dropping a 3.5 in a gun and havin' at it.
Actually, any shot gun will benefit from this but the bigger you get, the more pronounced it becomes. The question is, how crazy do you want to get? I have built card-cutter guns that will punch baseball sized holes in a target at 25 yards with almost no fliers. Practical? Not by a long shot. Accurate? You bet!
A shotgun bore is not a gutter pipe like most think it is. As we all know, in turkey hunting, the weapon is used more like a rifle than a shot gun.There for, we need to focus more on the ballistics inside of the gun as well as outside. The choke is only one piece of the puzzle.The forcing cone and bore-proper have just as much to do with the end result as the choke. Most guns and Loads do just fine with factory set-ups with a good choke. They will shoot minute-of -turkey all day , every day. If you are looking for the best, you need to look deeper. You have to ask yourself when good is good enough.
The whole craze of 3.5s, as stated by clark earlier, was to give waterfowlers a fighting chance with steel. It didn't take long for ammo makers to find out that the longer shot strings of the larger payloads in a 3.5 also gave better patterns when coupled with non-toxic lead substitutes like tungsten- poly or bismuth making the 3.5 very effective for watefowl
Turkey hunters grabbed at it because it extended their range. Its a give-n-take. If you get 60 pellets at 40 yards, you may only get 25 at 50, but thats 25 more killing pellets than you would have previously gotten. BUT....the recoil is much more pronounced due to the bigger load.
Blown patterns are not a symptom of choke or bore. Thats a myth. There is more to it than that and I wish it were that simple.
Southern Yankee asked why a pump kicks harder. well, the lock-up of a pump means you take ALL of the hit coming out of a load versus an auto loader which uses the energy of a shot (either gas operated or enertia) to cycle the next round. In that case, the gun takes a good percentage of the hit away from the shooter and puts it back into the gun making it much more pleasureable to shoot.