Disclaimer: Yet to use every weapon attachment in the world or gun. Obvious examples LMGs and Snipers with some ARs.
Gunsmith I have saved my attachments so don’t have to remember or setup every time I change guns.
Assault rifles
Normally run quickdraw/stock everything apart from XR-2/Shevia/M8A7 and KN44.
High cailber used when going for headshots, long barrel would only use it on XR-2/M8A7 or HVK-30. Not sure would be worth using due to lack of ranged maps.
Shevia with stock/Elo
Suppressor for KN44 with stock is not bad.
SMG’s
Extended mag for kuda, Quickdraw/laser for the VMP, Quickdraw for the Weevil, Fast mags / Extended mags or suppressor, Quickdraw / Stock for the Pharo , Red dot / Quickdraw for the Razorback.
Shotguns
Nothing on the KRM or Quickdraw / long barrel
Nothing on the Brecci or Fast mags / Extended mags
Nothing on the Haymaker or Fast mags / Extended mags
Nothing on the Argus or Quickdraw / Stock
Suppressor can work on the Brecci makes the weapon 2 hit kill with less range.
Perks
Normally use the following pretty much
Blind eye/cold blooded for anything that needs to be destroyed and engineer
Flak jacket
Dead silence/Awareness or Dead silence
Tracker/hard wired
Engineer for red wood
Scavenger
Must be noted been running with only two perks as of late for certain gamemodes. Fast hands/gung ho is good for shotguns plus ghost.
Equipment
EMP
Smoke
Trophy system
Thermite
Frag
Pretty much every class has black cell or XM-53 on it. Apart from shotguns which uses a pistol.