G.I. Joe 2: Retaliation is nearing the start of production, with a release date already set for July 29, 2012. Dwayne Johnson, who is portraying Roadblock in the action-packed sequel, is undergoing weapons training this week, and released a few photos from his training sessions. Click on the photos below, which feature Dwayne Johnson firing a Glock and M249 machine gun, to access our gallery.