If the military scenes in Joss Whedon's The Avengers look particularly authentic, that's because they are. According to an article on the U.S. Army's official homepage, 25 Army Reserve soldiers were used for filming in Cleveland alongside Captain America and the Avengers. The scene involved Army Reservists racing through the streets and blasting away with heavy artillery.
"The combat scenes had great realism," said Lt. Col. John Clearwater, deputy director for the Office of the Chief of Public Affairs, Los Angeles. "It's a tribute to the U.S. Army Reserves and the veteran 391st MP Battalion. They rocked the streets of Cleveland with their 50-caliber machine guns and Mark-19's. The film crew was blown away by their firepower and teamwork."
Many of the soldiers involved appreciated the chance to show moviegoers exactly what the Army Reserves can do, going so far as to make tactical suggestions on set. "It's easy for us to make on-the-spot corrections to tactics and uniforms," Staff Sgt. Michael T. Landis said. "The director actually took our recommendation on one scene and let us all engage the enemy as opposed to only the gunners in the trucks engaging."
That added dose of realism might not seem like such a huge deal, but aside from showing off the skills of the Army Reserves, these scenes will also bring the proceedings more down to earth, which is important when dealing with alien "gods," men in metal suits and the like.
Opening May 4, The Avengers stars Robert Downey Jr. as Iron Man, Chris Hemsworth as Thor, Chris Evans as Captain America, Mark Ruffalo as the Incredible Hulk, Jeremy Renner as Hawkeye, Scarlett Johansson as Black Widow, Samuel L. Jackson as Nick Fury, Tom Hiddleston as Loki, Clark Gregg SH.I.E.L.D. Agent Phil Coulson and Cobie Smulders as SH.I.E.L.D. Agent Maria Hill.