J over 3 years I shot a few squirrel with cci sv round nose. Two different times they were still alive and breathing with blood and brain running out of their head as there heart beat and were still moving feebly. Their skull was busted . The first tile I thought it was a fluk and would not have believed it had I not saw it. The second time I quit using them and round nose for squirrel. I don't understand it like you said I gave killed a ton of then with my .20 cal air gun.. but they hit the ground dead.
when I was a kid I grabbed the wrong ammo had round nose 22lr kept hitting that squirrel and it kept running finally dispatched it in a brush pile there was one round left in the magazine when we went to put the other in and it had been the mag that had been loaded with round nose.
yes J hollow points will nearly cut them in half at times , but there isn't hardly any meat in the middle and they don't go any where
and I hate loosing them to a hole in the tree it is a waste of a squirrel and time trying to figure out where they went