The response characterastics and the impact factors of typical propellant charges were discussed in terms of general methods of tailoring the propellants to counter mechanical threats by the bullet impact,where bullet type is a 12.7 mm armor-piercing projectile,and the impact velocity is (850±20) m·s^-1. The results show that there are obvious correlations with the propellant compositions,forms and the piercing depth in the vulnerability response extents by the bullet impacts,but the energy level of propellants. Also,there are obvious influence on the propellant vulnerability response for the restrained conditions to the propellants. The typical propellants have no violent reaction in the weaker restrained conditions.