Zero distance for squirrel hunting?

If you do use Chairgun, for squirrels and smaller targets, I set my "kill-zone" to .25 or 1/4 inch instead of .5 or 1/2 inch.

That way you will have a better idea of your holdovers outside of the PBR if you are not clicking for range. At least for me, 1/2 inch is too large to think of as a kill-zone on squirrels and smaller.

This is what I do using .177 because I am trying to make as accurate/precise shot placement for clean kills as I can on rats, chipmunks and tree rats which is usually a heart shot, but sometimes a head shot if a heart shot is not feasible. JMHO YMMV
 
My scope is a fixed 4 power, mounted close to barrel, my zero is set near the distance I expect to shoot.I don't dial to distance, and have never looked at chairgun or bought a camera to film my kills. And don't consider my airgun a long range appropriate platform. Yeah I know I'm stupid and ignorant. My only excuse is 60 + years of shooting made me this way.