Sturm Turret (Polygon mesh 3D model) is available on CGTrader for $7. Original author: Nifilim. Specs: 13398 polys, 15481 verts.
STL (Stereolithography, filesize: 1.46 MB), OBJ (OBJ, filesize: 1.88 MB), BLEND (Blender, filesize: 3.43 MB), FBX (Autodesk FBX, filesize: 756 KB)