The range would be too far for me and my rifles. A grouse has a head that is at the most 1" diameter. A rifle would need to be accurate to within an inch to be consistently effective for the game. I have three .22's that will group at a touch under an inch at 50 yds with good ammo from a bench rest on a calm day, but none that will consistently group within an inch at 100. From positions and rests generally available in the field, my wiggles will add about 1 moa of bullet spread to the group. So I limit head shots on grouse to 50 yds or less, and prefer to stalk close. Same principle as with big game, I like to stalk as close as possible at all times. I have never seen a forest grouse that was so wary that it would flush when stalked from 100- to 50 yds, and I have seen my fair share of grouse while hunting. I feel that long shot challenges are for targets, not living creatures. But, it is not as unsavoury as the current trend of ultra long range shots at big game, most of the negatives don't apply to grouse and head shots. So if you can do it, no harm done, you are unlikely to wound and lose many grouse in the attempt.
