Gas rapid unloading (GRU) is an innovative technology for ore comminution. Increasing the production of fine powder in each ore grinding cycle is vital for scaling up the GRU method to industrial applications. This study utilizes lab experiments to demonstrate that moderately reducing the orifice size significantly enhances pulverization and increases fine particle yield. Numerical simulations suggest that smaller orifices improve pulverization by increasing jet speed, reducing pressure drop, and creating a larger pressure difference inside and outside the unloading orifice. The orifice size should be optimized based on feed size to ensure efficient ore discharge. Reducing the unloading orifice size improves GRU grinding efficiency and energy use, offering guidance for the design of ore discharge ports in future industrial-scale equipment.