What's the smallest shot that is adequate for reliably whacking squirrels from typical squirrel whacking distance? #6? #7-1/2? #4?
I've never heard of piney squirrels till now. By the picture it looks like a mix of fox and gray squirrel.
Pineys are small.............this is a 10/22 for size comparison ('bout half the size of a reg fox squirrel, maybe even less).
Greys seem to be 2/3 to 3/4 fox squirrel size.