WW4 Extended is an unofficial expansion for the WW4 modpack, the OFP & CWA mod that focus on performance. It covers modern, Cold War era and Arctic warfare, adding numerous infantry units and vehicles for all sides, and provides several visual and sound effects (tracers, bullet cracks), support options and many other features.
The M113 is available if you decide to install the Cold War module. The M113 model was ported from ArmA 1. Screenshot by Apocalypse83.