G Gordon Liddy preached this decades ago, knowing how the JBT and bad guys were all going to be wearing that stuff.
Current SOP is to aim for the pelvis in case of body armor. It dismantles the body and renders it immobile very quickly. Easier to score hits than the head.
+1
Who cares if you miss a couple of times? If a jihadi is bad enough to keep his feces collected with bullets whizzing by his noggin, he deserves to get you.