A milling rotor includes a drum having a cylindrical wall disposed about a central axis of the drum. The milling rotor also includes a series of milling bit assemblies arranged in a spiral pattern on an outer surface of the cylindrical wall. The series of milling bit assemblies is configured to commence from a lateral plane that is transverse to the central axis of the drum and located partway along a length of the cylindrical wall. The series of milling bit assemblies is also configured to terminate proximate an end of the cylindrical wall. Each milling bit assembly is positioned such that an angle subtended by the series of milling bit assemblies with the lateral plane increases with increasing distance from the end of the cylindrical wall.