I often take a shotgun in the early part of the season. My 'go to' shottie for squirrels is a 20 Ga. Mossberg 500C, with a factory 26 inch vent rib barrel, and a modified choke. I use #6 shot, usually Federal.
My first long gun, and the gun I have taken more rabbits and squirrels with than any other, is an old Stevens 20 Ga single barrel, modified choke. It still has a place of honor in the gun safe.
Its always fun to find an old thread, and add something.