If the bullet is initially fired at sub sonic velocities then there would be no destabilization because there would be no shift in the pressure waves. Same would be true if a bullet were to remain super sonic. So long as it is sub sonic or super sonic there will be no shift in the pressure waves and no shift between high drag at sub sonic velocities and low drag at super sonic velocities. Only when the bullet (air plane, rocket, etc...) moves through the transonic region will this shift of pressure and drag occur.