Popped these 4 Saturday morning with my Hatsan Vectis .22 retrofitted with a DonnyFL Tatsu moderator. Pellet was H&N Baracuda Hunter Extreme. Nice expansion. Not as accurate as JSB 18's, especially past 30yrds, but they do fine within 30.
Those look like pretty beefy squirrels!
What scope are you using on the Vectis?