On grouse you have two good options for shot placement to save meat... best of course is the head shot, and it is not difficult with a scoped or red dot mounted rimfire rifle, no reason why you can't shoot a nickel every time at 25 meters. In this case, shoot whatever ammo is most accurate for you. The other option is the high back shot on a bird facing away from you. This shot breaks the back and will miss the breast meat. As for bullets, I like CCI Subsonic HP's most of the time, or 45 grain Quiets when big game hunting with folding/takedown rifles.
You are right, grouse that sit or stand still are very easy to shoot in the head out to 30, 40, maybe 50 yards.
Unfortunately, our Kootenay ruffed grouse do the tuck and dodge moves all while bobbing their heads as if they were
listening to a great Country song. We literally have to time the head bobbing so these birds actually walk right into the bullet......

LOL
Our grouse get very spooky, very quickly I might ad. This year they were doing the tuck, dodge, and head-bob moves only a few days into the season. Of course out here near Cranbrook, every guy and their dog hunts and shoots grouse......
The spruce grouse here on the other hand are so stupid, it's not even a challenge to shoot them, they will stand by while watching their brethren tip over. My wife and I stopped shooting spruce grouse over ten years ago. Blue grouse and ruffed grouse only for us. In addition to being stupid, the spruce grouse have extremely dark red meat and are like eating my hunting socks after a days hike....
The blue grouse have nice white meat, or at least until they get very old and or it's close to the end of November. Then the blues can get darker meat as well.
Ruffed grouse on the other hand are absolutely delicious. Their light colored white meat melts in ones mouth when handled properly. In the ole' days as a young man I used to hunt California Quail along the river dikes in the Okanagan Valley. And in the foothills along with Chukars and Hungarian Partridge. The California Quail are the elk/moose meat of game birds. They taste like white meat grouse tenderloin hors d'ouevres.
I remember Ringneck Pheasant, Chukars and Hungarian partridge all taste very similar, still not as good as ruffed grouse and California Quail.
I know some guys like the dark red meat of Spruce grouse, we just don't care for them and they are way too easy to kill. This is probably why the ruffed grouse are so spooky, everybody is trying to kill them!......

LOL