LoL That was a mistype I didn't see. You're right sorry. I thought you were trying to say that the ammo/guns didn't exist at a certain time that was relevant to the game. My bad.
First of all, I was referring to armor penetration, which has nothing to do with your scenario, because my 5.56 pierces your armor and kills you before you bruise me to death with your 9mm. Furthermore, I can hit you in the chest with a baseball bat and kill you while you're wearing a vest. How is it relevant?
Also, a 9mm? Care to claim a distance, load, bullet weight, and quantity? You overestimate it's energy. The 9mm isn't the load I would use to try and prove your point.
Chill out, gun queer, the point is how much realism do you really want? At a certain point, you're right, even a baseball bat can kill in one hit, so why start to argue realism in a video game.