[Build] PKM for lower levels who cannot kill the enemies
Laser - 1mW Laser
Optic - Monocle Reflex Sight
Stock - FORGE TAC Ultralight
Underbarrel - Snatch Grip
Weapon Perks - FMJ
T1 - E.O.D
T2 - Pointman
T3 - Amped
The most important thing that you should remind with this gun is, just consider that you have no Shift key. It means do not run. (Except when you just respawned)
PKM (Not only PKM but also other Light Machine Guns as well) has slower first firing speed than other guns. Thus it has a huge delay before it starts firing, you should just walk, not running on the battlefield.
Second, when you hear the message of enemy UAB, VTOL Jet, Helicopter, immediately go out of the buildings and prepare to shoot them down. With FMJ Weapon Perks, UAB or others go down so fast.
This will be your part. Reload your ammo when you hear the message, look for the sky and fire. Even VTOL will go down before it starts the attack. And with Pointman Perks, you can spend your scores without wasting.
It has extra slow reload time and enough much ammo (100 ammo) so do not reload it too often but always reload when enemy UAB, VTOL, etc are coming.
I assumed that we have so suck aim to kill enemy players, but there is always the way to earn scores. Since M4, 725 and others were nerfed, why don't you try this new strategy?