It's hard to port balance from real life to a video game. Weapons in real life are designed to be as effective as possible. Weapons in a video game are not created and tested in a vacuum. RL is hard to port because death is final. RL tactics are different and the stakes are different. Take the classic example as to why some rounds are hollow point and some are not. Hollow points hit a fleshy target and expand causing as much damage as possible. Solid bullets were used in wars to hit a soldier and only wound him. This resulted in medics being tied up, bogging down resources. Tactics are different IRL. Additionally, no sane soldier in a war really wants to kill other people. You can't expect realism in dayz. No one gets PTSD from a video game. Also, zombies aren't real.