Create Amazing Vector Graphics with Infinite Design v3.4.4 [Unlocked] for Android
In Metal Gear Solid: Peace Walker, the Patriot can be developed from design specs held by Kazuhira Miller, which are obtained during the "Date with Kaz" Extra Op. The description also references its infinite ammunition, although with a notably different explanation for it: claiming that it was because The Boss left a piece of herself inside it. In terms of the overall mission order, not counting the Monster Hunter related missions, the Patriot is also the last weapon/item to be developed in the R&D menu. Its development requirements after unlocking the design specs are an R&D level of 99, the completion of the M16A1 (w/shotgun) rank 4, and a member of R&D with the "Patriot" skill.
Infinite Design v3.4.4 [Unlocked]