Project Reality (PR) is a mod for Battlefield 2 . Project Reality's aim is to create a more realistic combat environment than standard Battlefield 2, and place a greater emphasis on teamwork and cooperation.

Most of the aspects of Battlefield 2 that have the capacity to be modified have been tweaked, or completely overhauled, to reflect their real life counterparts, for increased realism. Ballistics have for example also been audited to reflect those of real weapons, including characteristics such as damage, deviation and bullet drop depending on a weapon systems calibre.

You can download the mod from: http://www.realitymod.com/downloads#bf2 (battlefield 2 not required)
You will need a disk mounting tool such as daemon tools to install it though. less