Wow, this is me as a much younger guy. I am on the left and was only about 19 or 20 when this picture was taken. That is me and a buddy after the engine blew on our Sheridan. I was stationed at Fort Irwin more commonly called the NTC.
This is a Bradley M2/3 IFV or CFV depending on the unit. I believe that this is a shot from the opening days of OIF. The chain gun fires a 25mm round and in this shot it is "working out."