I tested out some Weapons and some even if aimed perfectly to Head or even Body don't reach the Target at all, the Target does not even notice anything...
So i assume the Distance has been capped, but only for the Player, because Enemy will hit you at a hilarious Distance with there AK47 while the Bullets of my Sniper Rifles don't even reach the Target, so the Distance are capped a bit strangely.
Also the Grenade Launcher acts weird too, the Grenades goes straight trough the Target and vanish without Explosion, so hit them directly is waste of Ammo, only splashing works.
And there also invisible Walls where you can't shoot trough, they are between Objects, like between Trees and Ground if they are near and other such Constellations, that is annoying because you aim perfectly a Headshot and the Target only starts noticing you, you shoot again in the Head, the Target knows wher eyou are end gets alerted, you shoot again in the Head and nothing and then well Alarm and Mission Restart...
But sometimes also Bullets goes trough solid Structures, most likely because there are invisible Holes between Textures, and because the Enemy are like Aimbots, they will hit that Pixelhole also the same happens for Detection, they see you trough those Pixelholes, i can hear it that they seen me trough Walls but because its only a Pixelhole they notice it too short for the Gauge to appear or to further getting alerted.