In order to study the response characteristics of cylindrical shelled propellant charges under the impact of the bullet, a kind of 12.7 mm bullet impact test was designed. The high-speed camera recorded the response of the shelled charges under the impact of a 12.7 mm bullet. Shell fragment velocities and air overpressures at different positions and azimuths were measured. Besides, the ideal detonation of the shelled charge was numerically calculated and the relative energy release rate was obtained. Four bullet impact tests of cylindrical shelled charge were carried out totally, in the first three tests, deflagration reaction occurred in the charge, and in the fourth test, almost no reaction occurred in the charge. Results show that the reaction and relative energy release rate are great influenced by the impact position. A time sequence response of ignition, smoking, extinguishment and low-pressure combustion occurred in the propellant when the bullet impacted vertically on the axis of the shelled charge, and its relative energy release rate was 1.146%. When the bullet impact position deviated from the axis by a distance, the propellant almost had no reaction, and its relative energy release rate was only 0.473%. The reaction of propellant can accelerate the shell fragments. When the deflagration reaction occurred in the shelled charge, the fragment velocity could reach 428.6 m·s^-1, while the maximum fragment velocity was only 70.1 m·s^-1 when the propellant almost had no reaction.