This papercraft is a life size Iron Man Mark XL (Mark 40), a Hyper Velocity Traveling Suit and was one of several new Iron Man Armors created by Tony Stark as part of the Iron Legion, based on the new Iron Man 3 movie, the paper model is created by Gaiatron.
The Mark 40 armor was created sometime between the Battle of New York and the Mandarin's Threats.
It was featured in Iron Man 3, and made its debut when Tony ordered J.A.R.V.I.S. to initiate the "House Party Protocol", in which it was activated along with the rest of the Iron Legion to aid Tony in his battle against Aldrich Killian.
The suit was named "Shotgun" due to the explosive sound it creates, like a real Shotgun itself when breaking the sound barrier in flight.
The armor was built for hyper velocity traveling, and specializes in high speed flights. It is currently known as the fastest armor among Tony's armor arsenal, with a speed of over the excess of Mach 5. [Source: wikia]
You can download this papercraft template here: Iron Man 3 - Life Size Iron Man Mark 40 Armor Papercraft for Cosplay Free Download [DropBox] [Box] [Gavitex]