M400 and M401

Rocket uses in

Functioning

Over-all length (M401), inches

2.58

General: These fuzes are similar in operation, the differences being in the dimensions and arrangement of the parts. Also, the M400 has a striker guide which is not in the M401. Both these fuzes are considerably safer to handle than the original base fuze in the 2.36-inch rockets, a fuze which had only a safety pin and detonator cover for safety devices.

Description: Both fuzes have a housing, or body, a striker, creep spring, arming pin, slider, slider spring, detonator holder, safety pin, and shipping clamp.

Operation: The shipping clamp can be unlatched and removed when the safety pin is latched and removed when the safety pin is taken out, before loading in the launcher. On set-back, the slider moves back against its spring, which action frees the arming pin from the binding action of the slider. The arming pin is now riding against the inside of the launcher, and, when the round leaves the launcher, the arming pin is shot out by its spring. The firing pin is now held by only the creep spring. On an impact equivalent to a 12-foot drop, it will overcome the spring to strike the detonator.

Figure 143. Army Base Fuze (Rocket) M400

Figure 144. Army Base Fuze (Rocket) M401