I've seen a few conversion kits and they kinda look cool but I always feel like there's some kind of hidden trick or something to them; after all if a belt-fed AR15 was a good idea why didn't the military make one? I'm somewhat sure there must be a reason why, and I'm at least 60% sure the answer isn't "it'd be awesome but the M249 is way better" but I don't know enough about engineering to say.