I have a 1945 Coey with an old 4x Weaver scope that has been used to kill ... loads of grouse and rabbits over the years.
I also have a single shot CIL/Anshutz with a 4x scope that shoots tiny holes at 50 yards. It too has had its share of grouse.
My latest is a Ruger 10/22 with a modified trigger, Shilen Select Match grade 20 inch barrel and A VICTOR CO USA stock. It shoots
.25 inch groups at 50 yards with Lapua 10x ammo, and has a Leupold 3.5-10 rimfire scope mounted on a rail with Warne removable rings. This thing
outperforms anything I have hunted grouse with before, and has taken ptarmigan, sharptail, huns, ruffed grouse, blue grouse, spruce grouse
as well as rabbits. Very fast, accurate and if I leave the scope set to its lowest power with the parallax set to infinity, is hard to beat IMHO.