THE issue. we've had "deep penetrating" .44 cap and ball, .45 Long Colt, .45 ACP ball for nearly 200 yrs now, and all are WELL PROVEN to not be worth a hoot. On the other hand, we have about 30 odd years of "only" 8-10" of penetration with 223 softpoiints, and DOCUMENTED cases of these rounds failures are VERY rare, given chest hits. Like 1 in 50 or less.
It's EASY to prove that the 223 sp is FAR superior to .45 ball on dogs, or hogs, or deer. No reason at all to think that anything changes when men are shot.