What is that on it's left arm? A shield-bazooka combo? If it is that is really badass.
Barrel's too short to be a bazooka. From the handlebar on top it's supposed to be held like minigun, but then the long shield bit won't make sense. Also, there's not enough ammo storage space in that shield.
Best deduction would be some kind of short-range shotgun/flak.
The colour scheme resembles the old Full Armor Gundam (before Thunderbolt ver.), but the armaments are different. I'm going to guess this is inspired by that.