Single barrel support is not uncommon, specially under the barrels (hey, even the assault cannon of 40k has one under). But having both on top and bottom of the barrel and bracing the muzzle, is a design thing I first see on your model, then on the Mastodon.
I am not a hard fan of Macross-genre armory, so maybe I missed something on the road.
C&D GW ? That would have been funny...
"Imitation is the sincerest [form] of flattery". Charles Caleb Colton
So keep inspiring FW team