Interior ballistic performance of unslotted single-perforated stick propellants in a large-caliber gun could be influenced significantly by erosive burning. To analyze erosive-burning phenomena, a comprehensive model, with special emphasis on the interaction of turbulence and combustion, was formulated to simulate erosiveburning processes occurring inside the center perforation of an unslotted NOSOL-363 stick propellant. The numerical results obtained from solving the theoretical model were validated by experimental data in terms of time variations of internal diameter distributions along the propellant grain. It was found that the erosive-burning phenomenon was caused by the enhanced heat feedback from the gas phase to the solid phase resulting from the combined effect of increased turbulence kinetic energy and turbulent heat-transfer rate.