One issue every noob starting in a NON rifleman role runs into, is that roles in airsoft arent very similar to roles in the military.
As a machinegunner myself, I can tell you that the most effective way to employ a 249 is to handle it like a rifle. Lmgs dont help your team when theyre laying prone 100ft behind you. Back we had a pair of 249s, we were always at least 50ft ahead of our riflemen. They were there to cover our flank, so technically they were the support.
Anyway, as im sure its been said, having a full auto only gun starting out would be bad if you dont understand fire control yet. And theyre expensive to run. I recall getting a kill every 25-150 rounds, compared to my vsr's 1-2 rounds and my m4's 1-10 rounds