M822, optimized for penetration to meet a NATO requirement to penetrate a steel helmet at 800 meters. Contrast that with well noted damage caused by M193 ball in RVN.

The Russian 5.45 has a long for caliber bullet with an aft CG to promote yaw and tumble. An idea the British put to good use in MkVII ball in 1910. As soon as the bullet hit the target and decelerated, its heavier lead base caused it to yaw violently and deform, thereby inflicting more severe gunshot wounds than a standard single-core spitzer design.

Like anything else, bullets are a compromise, "pays yer money and takes yer choice."