George,
One problem in talking chokes is that most people don't actually know the constriction of their choke, instead depending on what it's marked. I've measured "modified" 28-gauge chokes that had a constriction from the actuall bore diameter of anything from .010 to .020". That's quite a difference!
Plus, typical factory 28-gauge ammo has pretty hard shot, one reason it costs a little more. I've found that a modfified choke of .012 to .015" will put enough #6 shot in a 20" circle at 40 yards to kill roosters pretty well, even with 3/4 ounce loads.
One of my favorite 28-gauge pheasant handloads, however, is 7/8 ounce of hard #7 shot, the perfect compromise between 7-1/2's and 6's. I've never found a 28 that didn't pattern this load well, and 7/8 ounce has about as many pellets a 1-1/8 ounce load of #6 shot. American #7, by the way, is the equivalent of British #6, their standard pheasant shot, with about 290-300 pellets per ounce.
