Ehhh, depends on what your shooting and what kind of round, just like any other projectile.
All the ballyhoo came into being when the .223 was sold to the po-po as "the one true way" as a solution to 9mm 147 grainer overpenetration shootings and suits. The problem is (as always) that the policicrats focused only on the caliber (or the magic sword, e.g. HK54s) instead of the hunk o' metal that comes out of it or the trained hand and finger guiding it.
We have superweapons! There is no need to follow Rule #4 or train up our boys in Rule #4! The weapons will fire themselves and the city attorney will stop jumping up and down.
"Arguments of policy must give way to a constitutional command." Payton v. New York, 445 U.S. 573, 602 (1980).