Concept designs for weapons from my ECHOstorm story idea.
And because of any smart asses that jump to conclusions... These weapons are meant to be used by mech-suits called E.M.A.C.S [link]
in the story. Spec-wise, they are impossible for a person to use on their own due to size, weight, and ammo (chain gun and other anti-armor ammunition).
Also note the M-16 thrown in for size reference.