RR, How often do you need a second shot at the speed a semi can deliver it verses the speed in which you can cycle a lever, pump, or bolt? In my experience in small and big game hunting I have never needed that speed other than hog hunting sounders which is what my AR's are for. As far as for squirrels, my little Marlin lever .22L is pretty quick on second shots if needed.
need isn't the issue.
RR