I am 100% positive that abybody who has more than 1 k\d...

For me:

If I Play the SL9 with 30 Bullets Mag, my K/D is lower if I Play the SL9 with 60 Bullets Mag.

If I use the Thermal Sight with SL9 and 30 Bullets, my K/D is better again.

The Weapon itself make big Changes. My Gameplay is always the same.

Maybe People with Bad K/D Play the wrong Weapons, the wrong Sight and so on.