Centrifugal Primer-detonator

UNO proper shipping name— Fuzes, detonating

Explosive Components

Detonator, tetryl booster lead charge, tetryl booster charge, primer, black powder delay charge and relay.




SC 1340/98-IL TM 9-1300-251-20

M125a1 Booster

Type Classification:

Std AMCTC 3326 dtd 1965.


Point Detonating Fuze M572 is intended for use only with 175mm, HE projectiles at all charges, and is designed to withstand structurally tne acceleration forces involved.


The fuze is similar to, but structurally superior to Fuze M557. Fuze M572 consists essentially of Fuze M48A3 modified with an epoxy filler in the ogive cavity for reinforcement, and assembled with Booster M126A1 n an integral component. A superquick element in the head consists of a firing pin, firing pin support and Detonator M24. The body of the fuze is epoxy filled within the thin-walled ogive.

The fuze body contains a delay plunger assembly, and a selective setting device for superquick or delay action. The del ay plunger assembly includes a firing pin and Delay Element M2, consisting of primer M54, black powder delay charge, and Relay M7. The M125A1 booster consists of a brass booster body having external threads to fit projectiles having 2-inch diameter, iz threads per inch cavities, and internal threads to receive ftizes having 1.7-inch diameter, 14 threads per inch. An aluminum booster cud containing a 34Q*grajjW tetryl booster pellet is threaded to the booster body. The M125A1 booster internal configuration is that of tt eccentric rotor containing an M17 detonator held in an unarmed (out of line) position by centriAigal detents and • gear train mechanism which provides for delayed arming of the booster assembly until the projectile is approximately 200 feet from the muzzle, depending upon the weapon and charge being fired.


No action occurs until after the projectile has left the muzzle of the gun, when centrifugal force releases the flash tube interrupter, thus opening the flash tube. At the same time, the delay plunger is armed in preparation for impact by withdrawal of the plunger pins, also by centrifugal force. The delay mechanism of the booster provides an arming distance of 200 feet. Upon impact, the superquick firing pin is driven against Detonator M24, exploding the projectile. Should the superquick element fail, the delay train will still function, thus avoiding a dud. When the fuze has been preset for delay, the superquick element will still function but will have no effect because the interrupter blocks the flash tube. Projectile detonation will occur through Delay Element M2.

Tabulated Data:

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