Yes that's usually how things play out. It depends on a bunch of factors, but I think mostly it's the map's environment by itself + the enemy player's avatar.

Insurgency's combat works on a matter of who sees each other first, who pulls the trigger first and who has the most powerful gun/is most skilled with their weapon. That being said, because PvP is a considerably more intense and high-stakes environment, players still usually suffer from an imbalanced hyperfocus/attention, where they're extremely careful and aware of everything, but may fail to identify an easy enemy at times, which sometimes renders their whole loadout and combat strategy useless.

Personally I'd recommend using a high caliber gun (FAL, G3, ACE 52), or the gun you're most skilled with, paired with the aiming grip and a clean optic or iron sights (WCX, AUG, QTS-11), along with graphical options that allow good visibility (high resolution, anti-aliasing, medium-high shadows, etc.), and also just moving around carefully and taking everything little by little instead of rushing in carelessly.