Well if you want a GOOD LMG, it'll cost over 1000$
And by GOOD LMG, I mean one you can land on and it won't explode. You can cut down trees with my G&P 249 and it's 8.5kg fully loaded
My favorite tactic back when Lycan was still playing (he had a G&P 249 ranger, same ROF as me), was to use alternating burst fire. Essentially we would act as one M249 with a 5000round box mag, alternating fire between us so the enemy would think it was just one M249 firing quick bursts, or if we had a long pause, they'd think it was a trigger happy rifle that was reloading. Then as soon as they start to move up we let loose
Double M249's even at 900rpm still lay down a hell of a lot of fire!