A ground artillery mobile suit for mid-range support, it was co-manufactured by Karaba, an AEUG support organization, and Anaheim Electronics during the Gryps Conflict. It used the movable frame of the MSA-005 Methuss as a base, and taking references from the RX-77 Guncannon, it has two Vulcan guns and a pair of beam cannons. Despite this, the suit is not related to the Guncannon, its name was given by one of Karaba's leader, Hayato Kobayashi, who had piloted a Guncannon during the One Year War.
Other weapons of the suit are a shoulder-mounted beam gun and a handheld beam rifle, and almost all of its armor was newly designed. By using the transformation mechanism of the Methuss' frame, the Guncannon Detector can transform into its Artillery Form by kneeing and unfolding its front armor under its waist, forming a three-point support system for stable, highly precise artillery fire. This transformation process is instantaneous thanks to the frame’s excellent strength and responsiveness.
In U.C. 0087, the Guncannon Detector was manufactured by Karaba and Anaheim Electronics as a ground-use artillery mobile suit for mid-range fire support. It was known that two units were built and dropped by shuttle to North America. While one machine was destroyed in a failed landing attempt, the other was safely collected by Karaba. It was painted with a red color scheme and called Guncannon Detector by Hayato Kobayashi. The mobile suit's total production number was unknown, with there being various theories. After the Gryps Conflict, a small number of Guncannon Detectors were inducted into the Earth Federation Forces.