At the start of Chapter 2-1 you will be in a garage with two Humvees, lots of breakable crates, and a machine gun. Pick up any useful items including the machine gun and at the end of the game select 'Yes' to overwrite your current equipment. Then at the 'Main' menu continue the game and you will notice that you have gained your items. From here you can sell the machine gun back for quick money and repeat the process over again. Doing this is an easy way to help upgrade your weapons early in the game and max your ammo out.
Added by: Sanzano Aug 12th 2011, ID#7615