Certainly with a match-type rifle, high-end optics, and match-grade ammo, 1" groups at 100 yards is more than achievable with a .22LR. I am not talking about doubting those claims. But I hear people talking about taking their plinking rifle with a Tasco 4x32 scope and bulk-pack ammo shooting 1" groups at 100 yards, and I don't buy it. In other words, let me hand you my rifle with my ammo and let's see if you can get 1" groups at 100 yards consistently. I am sure there are people who could do it, but those would be truly exceptional shooters and not your normal person, and this relies on a lucky series of 5 or 10 consecutive consistent rounds from the bulk pack of ammo.
Note the OP was regarding shooting a Remington Nylon 66. This is not a match rifle. I don't think you are going to make head shots on squirrels on a regular basis at >100 yards with a Nylon 66.
Personally, with garden-variety ammo and sub-$300 rifles, particularly semi-autos, I think the "effective range" of a .22LR from your average shooter is more like 50 yards. If you want rimfire at 100+ yards, then .22WMR is more like it, and >200 yards, .17HMR. The momentum of the bullet in a .22LR is too small to keep the thing from being blown by the wind or dropping unpredictably at 100 yards.
MHO of course.
