From the preview:
GU-11 55mm Triple Barreled Rotary Cannon
The GU-11 is a hydraulically driven, triple barreled rotary cannon configured as a rifle. It fires 55mm High Explosive Armor piercing
(HEAP) rounds from an internal, stock mounted helical magazine at the rate of 750 rounds per minute. This weapon is durable, performs well in atmosphere and vacuum, and has excellent range and penetration. The
GU-11 is carried by hand in both Guardian and Battloid modes of all variants of the VF series Valkyrie variable fighter, as well as some non-variable UEDF forces.
Primary Purpose: Anti-Mecha and Assault
Weight: 350 pounds (157.5 kg) loaded
Range: 4000 feet (1,219 m)