I actually think Salvage is a decent good Perk with the MK14. You'd actually be surprised how quickly ammo can start running out with it, even if you're a good shot.
The Red Dot Sight is usually what I use with it. Doesn't really obstruct your view at all and with its accuracy, wherever you point the dot, it will pretty much hit.
ACOG would be if you're more of the longer range marksman type, but the increased sway and recoil hurts it a little. Though, the Hybrid Sights offer less sway and recoil, but really obstructs your peripheral vision with the scope.
A suppressor is nice either alone (iron sights aren't bad) or with a sight if you use Attachments.
Marksman being another good Perk to use with it, lol.
If you like to move around a bit, then Quickdraw is also nice to have. You could also replace Marksman with Stalker too if you want.
Rapid Fire isn't really necessary from my experience. Yes, using it removes the firing cap so it can fire as fast as you can tap the trigger, but that's not really how it's meant to be used from my experience. Only really useful for lucky-ass panic hipfiring, lol.
