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.
Mule Deer you are spot on with the choke and what the actual measurements really are. But .012 to .015 is LMod. Which I have found to be the best choke in 28ga guns.
