This game is also available on Xbox 360.
2) When you reach Chapter 4 "Higher Ground", the following message displays "New weapon parts available".
3) Enter Weapon Customization menu, enter the Primary weapon submenu and select the G36C weapon.
4) In the Stock section put the new "Rusty Stock" part. In the Suppressor section select the new "Soda Can silencer" part.
5) In the Front Mount section put the "Metal Plate" (which you have from the beginning).
6) When you back to the game, the Scavenger trophy message displays.