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Ordnance, Explosives, and Related Items

Navigation: Fuzes > Projectiles > United States

BI, Mk 10 Mod 3, 4, 9

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Description

This fuze consists of a single body unit containing a striker carrier, an anti-creep spring, and a primer magazine head. An integral tracer is located in the after end of the fuze body. In the unarmed position, as illustrated, the firing pin is held offset from the primer by a pair of centrifugal lock bolts. The firing pin is pivoted in the movable striker carrier, which is held away from the primer by an anti-creep spring.

Because of the peculiar shape of the firing pin, the effect of acceleration in the gun causes it to lag. This force is greater than centrifugal force; so  during the acceleration stage the striker cannot align itself with the primer. When acceleration ceases, centrifugal force takes charge and rotates the firing pin into alignment.

Functioning

When the projectile is fired, the gases from the propelling charge force a small firing pin into the tracer primer, igniting the tracer-starter mixture, which in turn initiates the tracer pyrotechnic. Centrifugal force causes the two lock bolts to move outward against their spring, unlocking the pivoted firing pin. The firing pin then rotates into the armed position, where it is aligned with the fuze primer. On impact, the striker carrier moves forward against the anti-creep spring, bringing the firing pin against the primer and initiating the black powder in the fuze magazine.

Hazardous Components

No information about hazardous components.

See Also

Nothing else to see.

Source(s)

OP 1664, Volume 1 - US Explosive Ordnance (1947)