Best TR LMG for long range

[Defcon I]

Ok, so I mainly play as TR Heavy and I'm wondering something. What LMG is the best for longer range support roles? I like to defend bases and support assaults by laying down covering fire. So I want to know, what gun has the best range or even better, the best accuracy. I am currently using the default with a grip and 4x scope and it works ok, I just have to baby the recoil a bit and judge where the bullets will fall, which I've noticed is harder since I turned my particle effects up. ODD. So is bullet velocity what I should look for? Is there a way to increase this? I'm just trying to get some feedback before I waste my certs on something. Thanks.