M249's are intimidating to see on the field but really no more effective and much more cumbersome than an m4 with a box mag and long barrel. I've known them to be troublesome too. If you want a big gun I'd go with an m14, my g&gebr long is awesome! Still heavy but not as bad as m249, better rate of fire though not adjustable but has semi option. No box mag either but I think you'll find that if you are just sitting there as a support gun emptying a box all day long, everyone will simply avoid you and find another way around and you'll be bored anyway.