I have used a 28 gauge O/U with fixed skeet chokes for many years of grouse hunting, with complete satisfaction. It doesn't take much to kill a grouse, but you gotta hit 'em.
So much depends on what constitutes an ideal grouse gun for an individual, such as (but not limited to): The environment you hunt in (not all grouse coverts are created equally), your individual ability to acquire the target/mount the gun/swing/shoot. What works for me may well not work for the next guy. My advice to newbies is to select a light fast handling gun that fits him, and start out out by trending toward more open chokes and adjust that according to the experience he accumulates, and then practice with it as much as he can. It's far more important to be physically fit and clear-headed, and put yourself where the grouse are, (and have a good dog) to be a successful grouse hunter than to be overly picky about the gun (as long as the basics mentioned above are covered). Meaning, a fat out of shape, wheezing, clueless oaf toting a waterfowl gun in virgin old growth forest with no bird cover, is going home with an empty game pouch. At least if that bumpkin were carrying a light 28 gauge he wouldn't be wheezing as much!
