To improve the anti-overloading ability of initiating explosive device under ammunition penetration target, polytetrafluoroethylene (PTFE) materials with varied thickness were added at the bottom or the outer wall of detonators to weaken the impact stress wave and the strength of inertial overload. The standard one-leg bridge-wire electric detonators were used as strengthening object. The mechanism and effectiveness of this reinforcement method were studied by gas gun experiment and numerical simulation. Experiment and the simulation results show that the buffer layer isolates the impact stress wave and cushions the mass inertia of the detonators. With the increase of gasket thickness, the overload acceleration and overload damage of detonator decrease gradually. When the buffer layer thickness is greater than 0.9 mm, the detonator has no obvious damage. The addition of PTFE materials on the detonator has an obvious protective function.