This is a rigged M4 found in a post-apocalyptic wasteland with the subsequent modifications you would expect from such a place. There are two .OBJ files included, one low poly version and one high poly version. The original .blend is also included, along with all of the textures used.
BLEND (Blender, filesize: 93.5 MB), OBJ (OBJ, filesize: 93.5 MB), FBX (Autodesk FBX, filesize: 93.5 MB)