The M16 is extremely underpowered for what it should be.
Today as one example, I shot a Soviet 6 times in the head at point blank range and watched the blood fly, heard him scream. The Soviet helmet in use at the time was only effectively able to stop 9x19mm not 5.56mm at less than a meter away.
In return I got 10 rounds pumped into me while this guy was still alive after 6 rounds into his head at point blank range causing me to die.
This has been a pretty regular thing, which is why people prefer the Soviet side due to the AK being at the power level that it should be.