Video The video was filmed by members of a JTAC (Air Force Joint Tactical Air Controllers) in Tal Afar, a town west of Mosul. The JTAC was with a Marine Advisor Support Team (which was attached to an Iraqi unit to help with training. The Marines and the JTAC were ambushed by three hostile gunmen. The Marines returned fire, while the JTAC called in some air support. One of the JTAC troops set up a video camera on the front of their armored hummer, which they were using for cover.
What you hear is shooting back and forth. The metallic ping sound is enemy rounds hitting the hummer.
When one of the JTAC guys says, "just fired rifle" he means that the aircraft overhead has launched a Maverick missile. You can hear the missile approaching, and see it hit the vehicle that the anti-government gunmen were hiding behind.