If the adversary is wearing body armour or is partially covered, center of mass may not be effective.
Jus' sayin' ...
In general, first shots go to CoM.
Also, shooting hips or thighs is almost as likely to kill the adversary as shooting CoM. A ruptured femoral artery is often fatal.
Hence the “Mozambique drill”. If two on CoM don’t work, head next.
A 40 cal. bullet hitting body armor will still knock you on your ass.
Just sayin'.