DATA:

BOMBS USED IN

FUNCTIONING

ARMED CONDITION

FUZES USED WITH

ARMING TIME

MAX. BODY DIAMETER

OVERALL LENGTH

MATERIAL

GENERAL:

The M142 fuze supersedes the M3 nose fuze. The M3 fuze was used in experimantal production of the M74; however, it was found that the 1 to 2 second delay incorpora-ted in this fuze was unnecessary, as the inherent delay was sufficient. Therefore, it was re-designed and designated the M142.

The M142 fuze is an all-ways action fuze which screws into the nose of the bomb. This fuze consists essentially of a steel head and arming pin retainer, steel striker pin and safety pin; zinc alloy die casting striker, sleeve, fuze casing and arming pin; M26 percussion primer, cavities in end of case filled with 1 gram of fuze powder, and a zinc booster cup filled with 3 grams of propellant powder.

The M3 differed in that it had a M29 percussion primer, builtin delay charge compri-sed of a lead spitter fuze (potassium nitrate, sulfur and charcoal) capped at both ends by match compostiion (60% black powder, 40% collodion) and a cellulose nitrate boos-ter cup filled with 1 gram of fuze powder.

OPERATION:

The retaining pin is removed when the fuzed bombs are assembled in the cluster. While the bombs are in the cluster, a spring loaded release clip holds the arming pin in the body of the fuze. Upon release from the cluster, the release clip springs off allowing the arming pin to jump out under action of its spring. This action permits the safety pin to enter the cavity in the striker, and the fuze is armed. Impact forces the striker and sleeve together, causing the striker pin to pierce the M26 percussion primer, which in turn initiates the cavity charges and booster charge.

REMARKS:

The M26 percussion primer is better than the M29 since it will function even on soft surface impact.

See M74, page 110, showing M142 fuze assembled in bomb.

M142A1 (E9R23) will replace M142 because latter cannot be resafed after arming pin is released. Release pin can be re-inserted in M142A1. M142 fuze is reclassified as sub-stitute standard.