Std Jan


Proximity Fuze M732A2 is used with standard and rocket-assisted high-explosive 105mm cartridges and 155mm and 8-inch projectiles. The fuze was designed as an improvement over the M732 Fuze for compatibility with RAP rounds and top zone ballistic environments.


Fuze M732A2 is a continuous-wave, radio doppler proximity fuze capable of being set for proximity airburst or PD. Externally, the fuze has a plastic nose cone crimped to an aluminum collar, which threads onto a steel fuze sleeve. The collar retains a movable aluminum setting ring which has an index mark, The fuze sleeve is marked with contrasting black paint in 2 second increments in the range of 4 to 156 seconds and a PD mark. Time settings are used in the proximity mode only.

The fuze is set by simultaneously depressing two locking pushbuttons (within ogive) and rotating the setting ring to align the index mark to the desired mark on the sleeve (the fuze is shipped with index mark set on PD mark). When pushbuttons are released, the setting ring is locked in place.

Internally, the fuze consists of four modular subassemblies: the proximity detector, the timer and setting ring assembly the ("minor redesigned" PS 115) power supply assembly, and and S&A device with associated explosive train.


Upon weapon firing, setback and spin forces act upon the S&A module and the power supply. Setback force retracts a pin from the S&A rotor while spin unlocks two spin-locks and drives the rotor from safe to the locked-in armed position at 400 calibers of air travel, Meanwhile, setback actuates cutters that open the battery ampule to release the battery acid; spin disperses the battery acid into the cell stack to activate the battery.

When set for proximity function (time-totarget setting), the proximity firing circuit is armed at 2.8 seconds prior to the set time and the proximity element initiates the explosive train and detonates the round approximately 7 meters above target.

When set for PD, the proximity firing circuit does not arm. Upon impact with target, the S&A assembly slides forward and the M55 detonator (in the rotor of the S&A) is stabbed by a firing pin, which is restrained between the S&A module and detonator block, The output of the M55 detonator propagates through the explosive train and detonates the round.

If the fuze fails in the proximity mode, the fuze will function on impact.

Tabulated Data:


Visible 3.76 in.

Overall 5.97 in,

Temperature Limits:



Arming Data:

Method --------------------------------- Setback and spin and electronic signal

Fully armed -------------------------- 2,8 seconds before set time; 400 calibers in flight for PD

Min Max

Spin 1100 rpm 30,000 rpm

Setback 800 g 30,000 g

M2A1 container; 2 containers in wirebound box

*Packing Box:

Dimensions ------------------------ 14-5/8 x 1213/16 X 9-1/8 in.

*NOTE: See DOD Consolidated Ammunition Catalog for complete packing data including NSN'S.

Shipping and Storage Data (Interim):

Storage compatibility group ----- D


DOT designation -------------------- DETONATING FUZES, CLASS A EXPLOSIVES, HANDLE CAREFULLY, DO NOT STORE OR LOAD WITH ANY HIGH EXPLOSIVES DODAC -------------------------------- 1390-N291

Explosive Components:

Microelectric Detonator M55 Stab Detonator Lead (S&A) Lead (Fuze)

Booster Standard Comp A5




SC 1340/98-IL SB 700-20 TM 9-1015-203-12 TM 9-1015-234-10 TM 9-1025-200-12&P TM 9-1025-211-10 TM 9-2350-304-10 TM 9-2350-311-10

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  • tanja
    Who identification marks detonator SB?
    9 years ago

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