[1] The system consisted of a 37 mm T250 six-barrel rotary cannon mounted on a modified M113 armored personnel carrier chassis.

The designer, the Sperry Utah Engineering Laboratory, later revived the Vigilante, rechambering it for NATO-standard 35×228mm rounds and mounting it on a M48 Patton tank chassis for the Division Air Defense (DIVAD) contest.

However, it ultimately lost to Ford's M247 Sergeant York (twin 40mm Bofors) that also failed to enter service.

[1] It had a 192-round drum magazine, which in the maximum 3,000 rpm mode would have equated to approximately 4 seconds of fire.

The Sperry Utah Engineering Laboratory was selected to handle the integration of the T250 gun with the modified M113 chassis to create the T249.