Impact fuzes

This is the American M557, a high-explosive (HE) fuze, with fragmentation, delayed action, and a 0.05-second delay action.

• Impact fuze, fragmentation with delay: 0.05 sec
• Color: metal
• Material: metal casing
• Overall length: 12.7 cm
• Length: 9.9 cm
• Overall diameter: 6.1 cm
• Thread diameter: 5.1 cm
• Weight: 620 g
• Self-destruction mechanism: absent
• Fuze activation: 50 m after leaving the barrel
• Suitable for projectiles: M107, M549, M795, and many others

Also used in 105 mm guns: M101, M102, M119

The fuze is screwed into the projectile’s main well and tightened using a wrench. To set the fuze:

• For impact action, use a wrench or flathead screwdriver to turn the plunger slot to the “SQ” position (the SQ – Super Quick position is the default setting. Ensure the fuze indicator points to SQ).
• For impact action with delay: use a wrench or flathead screwdriver to turn the plunger slot to the “DELAY” position.

Cautions:

• Heavy rain may cause premature activation of the fuze during firing.
• Firing at low barrel elevation angles with the fuze set to “DELAY” may result in a failure to detonate the projectile.
• Firing at mortar angles (elevation greater than 750 mils) may result in a failure to detonate the projectile.
• Storing in a damp location (such as a dugout) can cause moisture absorption, leading to a failure to detonate. Fuzes that have become wet can be “dried” and returned to working condition.

Impact fuze, with instant action, inertia action, and delay action, adjustable by turning the selector and screwing (unscrewing) the cap.

• Fuze weight: 420 g
• Full fuze length: 10.57 cm
• Length of detonator inserted into the projectile: 4.68 cm

For arming:

• Required rotational speed: 3100 rpm
• Drop protection height: 1.75 m
• Protection: hermetically sealed, waterproof
• Fuze activation: 10 m after leaving the barrel
• Delay time: from 0.027 to 0.063 s
• Operating temperature range: from -40°C to +50°C
• Shelf life: 15 years

• Fuze setting for fragmentation action: the crane arrow points to the “SQ” mark, the cap is unscrewed.
• Fuze setting for high-explosive action: the crane arrow points to the “SQ” mark, the cap is screwed on.
• Fuze setting for delayed action: the crane arrow points to the “Delay” mark, the cap is screwed on.
• The crane is set using a special key.

Drop protection height: 1.75 m
Hermetically sealed, waterproof
Do not use with the cap unscrewed during rain.

The M739/M739A1 impact fuze is a modern fuze designed for high-explosive artillery shells. Key features:

Type: Instant-action impact fuze with a delay option.
Modes: Adjustable to two settings — instant action (SQ — Super Quick) and delayed action (DELAY).
Purpose: Provides maximum target destruction, both with surface impact and delayed action for penetrating fortifications.

Features:

• Instant Action: Activates on surface contact, ensuring effective destruction of exposed targets.
• Delay Function: Allows the fuze to activate shortly after impact, improving effectiveness against fortified or buried targets.
• Sealed and Waterproof: Suitable for use in adverse conditions.
• Arming: Activates by the shell’s rotation after firing, ensuring safe transportation and installation.

The M739/M739A1 is widely used for 155 mm shells and is employed in modern artillery to achieve high precision and effectiveness in targeting various objectives.

• Fuze weight: 680 g
• Full fuze length: 15.2 cm
• Visible length: 9.55 cm

Hermetically sealed, waterproof

Fuze Setting:

The fuze is screwed into the projectile’s main well and tightened using a wrench.

To set the fuze:

• For impact action, use a wrench or flathead screwdriver to turn the plunger slot to the “SQ” position (SQ – Super Quick), which is the default setting. Ensure that the fuze indicator points to SQ.
• For impact action with delay: use a wrench or flathead screwdriver to turn the plunger slot to the “DELAY” position.

Drop protection height: 1.75 m
Hermetically sealed, waterproof
Do not use during heavy rain.

Impact fuze with inertia arming system M78 (M78A1) is used with concrete-piercing shells of calibers ranging from 75 mm to 280 mm, except 175 mm.

The M78 (M78A1) fuze consists of two parts: the fuze itself and the M25 booster, which are separate components but are supplied and packaged together. The M25 is specifically designed for the M78 series fuzes and cannot be used with other fuzes.

M78 (M78A1) fuzes come in two types: without delay (for use on flat targets) and with a 0.025-second delay (for use on concrete targets).

The M78 (M78A1) impact fuzes without delay have a nose section painted white, approximately 2.5 cm wide from the tip. The fuze has a durable case made of hardened steel with an oval nose. The fuze case contains a striker and an inertia-type delay plunger mechanism with a detonator. The delay plunger is locked by two spring pins.

Functioning: After firing, the inertia force detaches the pin from the lock. As the projectile’s spin speed increases, the centrifugal force removes two plunger pins in the delay mechanism at the detonator head, thus arming the delay plunger. Simultaneously, centrifugal force pulls the safety pin away, allowing the rotor to rotate the hinged pin until the detonator aligns with the ignition hole in the upper part of the charge. The rotor is locked in the active position by a centrifugal catch during the subsequent trajectory of flight. Upon impact, the delay plunger moves forward by inertia towards the firing pin and initiates the explosion.

• Fuze weight: 907 g;
• Full fuze length: 7.62 cm;
• Visible length: 5.08 cm;

Fuze Installation: The fuze is screwed into the projectile’s main eye and tightened with a key. To install the fuze: For impact action, the plunger slot must be turned to the “SQ” position using a key or flat screwdriver. (The SQ position—Super Quick—is the default position. Check that the fuze indicator points to SQ.) For impact action with delay: the plunger slot must be turned to the “DELAY” position using a key or flat screwdriver.

M841 – South African high-explosive (HE) impact fuze (PD) with settings for fragmentary (SQ) or delayed action (Delay).

Key Features:

• Type: Impact fuze with adjustable settings between instant (SQ – Super Quick) and delayed (DELAY) actions.
• Usage: Designed to achieve maximum damage to targets both in open terrain and for penetration into fortified structures.

Features:

• Instant Action (SQ): Activates upon contact with the target, ensuring effective damage to open targets.
• Delay (DELAY): Allows for activation with a slight delay after impact, enhancing effectiveness against hardened targets or buried objects.
• Sealing and waterproofing make it suitable for use in challenging weather conditions.

M841/M841A1 is widely used in modern artillery shells and is employed to engage various targets with high precision and effectiveness.

• Drop Protection: – 1.8 m
  
• Sealed and Waterproof

  Caution: Do not use during heavy rain.

  Features:

  • Instant Action (SQ): Activates upon contact with the target, ensuring effective damage to open targets.
  • Delay (DELAY): Allows the fuze to activate with a slight delay after impact (0.05 seconds), enhancing effectiveness against hardened targets or buried objects.
  • Sealing and waterproofing make it suitable for use in challenging weather conditions.

The fuze is screwed into the projectile’s main eye and tightened with a key.

To install the fuze:

For impact action, the SQ position – (Super Quick) is the default position; check that the fuze indicator points to SQ. If it is misaligned, adjust the plunger slot to the “SQ” position using a key or flat screwdriver.
For impact action with delay: the plunger slot must be adjusted to the “DELAY” position using a special key or flat screwdriver.

Drop Protection: – 1.8 m
Sealed and Waterproof
Caution: Do not use during heavy rain.

KZ 984 is a Slovak high-explosive (HE) fuze designed for 155 mm projectiles such as HEER HB, HEER BB, ERFB-BT, and ERFB-BB. The key features of KZ 984 include:

Type: Impact fuze with instant action (PD – Point Detonating) with the option for delayed action.
Designed for high-explosive and other types of munitions where high accuracy and reliability upon impact are crucial. The fuze can be set to two modes: instant action (Super Quick) for engaging open targets and delayed action (Delay) for engaging covered targets or objects.

Features:

Sealing and waterproofing make it suitable for use in all weather conditions.
Protected against falls from a small height, reducing the risk of accidental activation.
The impact mechanism activates upon contact with the surface, ensuring the detonation of the charge.
This impact fuze includes a detonator booster and safety mechanism. It can be set for instant action or for a delay of 0.04 – 0.09 seconds.

• Fuse weight: 700 g
• Fuse length (full): 14.3 cm
• Visible length: 5.16 cm
• Fuse activation after exiting the barrel: 12 m

The fuse is screwed into the projectile’s nose socket and secured with a wrench.

To set the fuse:

• For impact action, position “O” (Open) is the default setting. Ensure the fuse indicator points to “O.” If not, use a wrench or flathead screwdriver to move the plunger slot to the “O” position.
• For impact action with delay, use a special wrench or flathead screwdriver to move the plunger slot to position “Z” (Closed).

Operation with a damaged nose is prohibited.

Its airtightness and waterproofing make it suitable for use in any weather conditions, except heavy rain. It is protected from falling from a low height, reducing the risk of accidental activation. The impact mechanism triggers upon contact with a surface, ensuring charge detonation.

The DM211 fuse is a Norwegian variant of the M557 fuse, used on 155 mm and 203 mm caliber guns. Unlike the M557, it does not have issues when set to delayed action or during mortar firing (no duds occur). The fuse arms itself at a distance of 50 m from the gun, ensuring crew safety.

The DM241 is the German variant of the DM211. The main difference between them is that the DM241 arms itself at a distance of 66 m.

Key characteristics of the DM211/DM241 fuse:

• Type: Point Detonating (PD) impact fuse with a delayed action option.
• Application: Used for 155 mm caliber shells and other artillery munitions where high precision in target engagement is required.

Features:

• Instant Action (Super Quick, SQ): Activates upon direct contact with the target, providing quick neutralization of exposed targets.
• Delayed Action (Delay): Allows detonation delay, which is effective for engaging fortified targets or objects under cover.
• Waterproof and Sealed: Suitable for use in all weather conditions.
• Resistance to Drops from Low Heights: Enhances safety during transportation and installation.

The DM211/DM241 is widely used in modern artillery, providing high effectiveness under various combat conditions.

• Fuse weight: 988 g
• Fuse length (full): 15.2 cm
• Visible length: 9.6 cm
• Fuse activation after exiting the barrel: 50 m (DM211), 66 m (DM241)

The fuse is screwed into the projectile’s nose socket and secured with a wrench.

• For impact action, the “OV” position is the default setting. Ensure the fuse indicator points to “OV.” If not, use a wrench or flathead screwdriver to move the plunger slot to the “OV” position.

• For impact action with delay, use a wrench or flathead screwdriver to move the plunger slot to the “MV” position.

This is an equivalent of the M557 fuse, with identical weight and ballistics.

The DM211 and DM241 fuses do not have moisture-related issues, unlike the M557 fuse. They are also allowed for use in rain (except heavy downpours).

Impact fuze KTA 7962, an analogue of RGM-2 with an adapted mounting interface for NATO standards.

Impact fuze, fragmentation and high-explosive action

• Color: Metal
• Material: Metal casing
• Overall length: 9.7 cm
• Visible length: 5.16 cm
• Weight: 0.4 kg
• Self-destruct mechanism: None
• Fuze activation distance after leaving the barrel: 15-30 m
• Compatible with projectiles: KTA5912, KTA5834, and others

The fuze is screwed into the main eye of the projectile and tightened using a wrench.

• Setting the fuze to instant action: The crane arrow is in the position pointing to the mark “O”, and the cap is unscrewed.
• Setting the fuze to inertia action: The crane arrow is in the position pointing to the mark “O”, and the cap is screwed on.
• Setting the fuze to delayed action: The crane arrow is in the position pointing to the mark “C”, and the cap is screwed on.

Note: The factory setting of the fuze is for impact action, with the crane arrow pointing to the position “O”.

DM371 is a German high-explosive (HE), steel, concrete-piercing, impact-inertia, point-detonating (PD) projectile fuze, sometimes known as the “Wallbuster.”

The DM-371 casing is made of hardened steel, which not only protects the fuze mechanism and firing system but also allows it to penetrate concrete structures.

The fuze is equipped with a pyrotechnic delay of 10 to 20 milliseconds.

Reliability in operation is ensured by the fact that the detonating mechanism is located in the rear part of the fuze.

• Overall length: 12.43 cm
• Weight: 1.14 kg
• No settings for different types of fuze actions are provided.

Screw the fuze into the projectile using a wrench.
The arming of the fuze occurs during the firing process, with rotation at 3000 rpm.

PD544 is a mechanical fuze with impact and delayed impact functions. It is designed for use with high-explosive (HE) artillery shells of 105 mm and 155 mm calibers, including extended-range ammunition, for artillery systems with barrel lengths of 39, 45, and 52 calibers.

The fuze can also be used with 120 mm rifled mortars, providing full functionality with all charges, including charge 0. Fuze arming is initiated by inertial and rotational forces at a safe distance from the muzzle. The striker and SQ (Super Quick) detonator ensure instant action upon impact. The delayed action device is located in the rear of the fuze and provides a 60 ms delay for activation.

Fuze with impact and delayed impact functions:

• Fuze weight: 595 g
• Arming rotation speed: 2900 rpm
• Maximum rotation speed: 25000 rpm
• Fuze activation distance from muzzle after leaving the barrel:
  • For 155 mm guns: 200 m
  • For 105 mm guns: 150 m
• Operating temperature range: -46°C to +63°C

Fuze installation:

The fuze is screwed into the projectile’s main eye and tightened using a wrench.

To set the fuze:

For impact action, the position SQ – (Super Quick) is the default setting. Ensure that the fuze indicator points to “SQ.” If not, use a wrench or a flathead screwdriver to move the plunger slot to the “SQ” position.

For delayed impact action: Use a special wrench or a flathead screwdriver to move the plunger slot to the “DELAY” position.

PDM572 is a mechanical artillery fuze with impact and delayed impact functions. It is designed for use with 155 mm high-explosive artillery shells.

The fuze arming is initiated by inertial and rotational forces at a safe distance from the muzzle. The striker and SQ (Super Quick) detonator, located in the nose section, ensure instant action upon impact. The delay device with an inertial striker is located in the rear section of the fuze and provides a delay of 20 to 60 ms.

The fuze is similar to, but structurally better than, the American M557 fuze. The main difference between the M572 and M557 is that the cavity of the M572 is filled with approximately 71 g of epoxy resin, providing overall rigidity to the fuze structure, allowing it to withstand increased acceleration forces.

Fuze with impact and delayed impact functions:

• Fuze weight: 970 g
• Arming distance: 33 m, at a speed of no less than 472 m/s
• Delay action time (DELAY): 0.05 s

Fuze installation:

The fuze is screwed into the main eye of the projectile and tightened using a wrench.

To set the fuze:

• For impact action, the position SQ – (Super Quick) is the default setting. Ensure the fuze indicator points to “SQ.” If not, use a wrench or a flathead screwdriver to move the plunger slot to the “SQ” position.
• For delayed impact action: Use a special wrench or a flathead screwdriver to move the plunger slot to the “DELAY” position.

An improved version of the American fuze M557. It has no issues during mortar firing. Unlike the M557, when set to the “DELAY” position, activation will occur reliably. It is resistant to moisture.

Prohibited for use in rain.

MK399 MOD 1 is a mechanical artillery fuze with impact and delayed impact functions. It is designed for use with 155 mm high-explosive artillery shells.

The fuze arming is initiated by inertial and rotational forces at a safe distance from the muzzle. The striker and detonator provide instant action upon impact (PD) and are located in the nose section. The delay device with an inertial striker is located in the rear section of the fuze and provides a delay of 0.009 seconds.

Fuze with impact and delayed impact functions:

• Fuze weight: 0.45 kg
• Arming distance: 60 m, at a speed of no less than 472 m/s
• Delay action time (DELAY): 0.009 s
• Operating temperature range: -40 to +70°C
• Length: 152.4 mm

Fuze installation:

The fuze is screwed into the main eye of the projectile and tightened using a wrench.

To set the fuze:

• For impact action, the (PD) position is the default setting. Ensure that the fuze indicator points to “PD.” If not, use a wrench or a flathead screwdriver to move the plunger slot to the “PD” position.
• For delayed impact action: Use a special wrench or a flathead screwdriver to move the plunger slot to the “DELAY” position.

Prohibited for use in heavy rain.

The M15 UTIU is a mechanical artillery fuze from a Serbian manufacturer, with impact and delayed impact functions. It is designed for use with 155 mm high-explosive artillery shells.

The fuze arming is initiated by inertial and rotational forces at a safe distance from the muzzle. The striker and detonator provide instant action upon impact (PD) and are located in the nose section. The delay device with an inertial striker is located in the rear section of the fuze and provides a delay of 0.02-0.05 seconds.

Fuze with impact and delayed impact functions:

• Fuze weight: 0.7 kg
• Length: 152.4 mm
• Safe when dropped from height: 3 m
• Operating temperature range: -30ºC to +50ºC
• Arming distance: 10 m, at a speed of no less than 472 m/s
• Delay action time (DELAY): 0.02 – 0.05 s
• Shelf life: 10 years

Fuze installation:

The fuze is screwed into the main eye of the projectile and tightened using a wrench.

To set the fuze:

• For impact action, the (SQ) position is the default setting.
• For delayed impact action: Use a special wrench or a flathead screwdriver to move the plunger slot to the “DELAY” position.

Moisture-resistant.
Prohibited for use in heavy rain.

The M02-P1 is an impact fuze (PD) with both instant action (SQ) and delayed action (DELAY), which is adjusted by rotating a selector. Manufactured in Serbia, it is designed to be fitted with high-explosive artillery shells with a bore (with adapter) of 100 mm, 105 mm, and 155 mm, and with thread adjustments for 122 mm, 130 mm, and 155 mm.

The arming of the fuze is initiated by inertial and rotational forces at a safe distance from the muzzle. The striker and detonator provide instant action upon impact (PD) and are located in the nose section.

Fuze with impact and delayed impact functions:

• Fuze weight: 950 g
• Safe when dropped from height: 3 m
• Operating temperature range: -40ºC to +50ºC
• Arming distance: 10 m
• Minimum arming rotation speed: 3000 rpm
• Delay action time (DELAY): 0.02 s
• Shelf life: 15 years

Fuze Installation:

• Setting the fuze to instant action: The crane arrow should be in the position pointing to the mark “T,” which corresponds to Super Quick (SQ).
• Setting the fuze to delayed action: The crane arrow should be in the position pointing to the mark “Y,” which corresponds to Delay.

Moisture-resistant.
Prohibited for use in heavy rain.

Description
The M51A5 point-detonating fuze is a selectable fuze with superquick action or a delay of 0.05 seconds, designed for detonating high-explosive projectiles of calibers ranging from 75 to 105 mm.

The M51A5 fuze consists of the M48A3 fuze combined with the M21A4 booster. The fuze’s main body includes a striker held in position by a support that prevents activation of the M24 detonator until impact. The fuze housing incorporates the M1 delay plunger block and an interrupter assembly with a setting sleeve, allowing the selection of either the superquick (PD) mode or the delayed function.

Components of the M51A5

The delay plunger includes a striker and the M2 delay element, which contains an M54 primer, a black powder delay charge, and an M7 relay. The main part of the fuze is attached to the body via a flash tube, which also holds the windshield or ogive.

The ogive is a thin-walled stamped steel component that provides the fuze with an aerodynamic shape. The M21A4 booster consists of a brass housing with external threads (2 inches, 12 threads per inch) for projectile installation and internal threads (1.7 inches, 14 threads per inch) for attaching primers.

The aluminum booster cup contains a 340-grain tetryl pellet attached to the booster housing. The internal configuration of the M21A4 booster includes an eccentric rotor that holds the M17 detonator in a safe position via centrifugal and setback locks. Upon activation, the locks release, and the rotor aligns with the fuze charge and flash tube if set to the superquick (PD) mode, or with the delay plunger charge if configured for delayed action.

Table of Characteristics:

• Type: Point-detonating (PD)
• Weight: 0.96 kg
• Length:
  • Visible part: 95 mm
  • Total: 151 mm

Temperature Limits:

• During firing:
  • Lower limit: -40°C
  • Upper limit: +51.7°C
• For storage:
  • Lower limit: -62°C (no more than 3 days)
  • Upper limit: +71°C (no more than 24 hours)

Explosive Components:

• Superquick Mode (SQ):
  • M24 detonator, M17 detonator, primary tetryl charge, booster tetryl charge.
• Delay Mode:
  • M1 delay plunger block (M2 delay element, M54 primer, black powder delay charge, M7 relay), M17 detonator, primary tetryl charge, booster tetryl charge.

Warnings:

• Premature detonation: (Details in “Usage Specifications”)

The fuze is screwed into the projectile’s nose cavity and secured using a wrench.

To set the fuze:

– For point-detonating (superquick) action, turn the plunger slot with a wrench or a flat-head screwdriver to the “SQ” position. (The “SQ” position—Super Quick—is the default setting. Ensure that the fuze indicator points to SQ).
– For delayed action, turn the plunger slot with a wrench or a flat-head screwdriver to the “DELAY” position.

Recommended for Prohibition in Use

Ammunition Name: M51A5 Fuze

• Batch: LOT SHX 3-24, LOT JHE 1-4
  Reason: Shell detonation upon exiting the barrel.
  Order Date: 24.07.2024, № 785/11/691/dsk
  Decision: Prohibited.

• Batch: LOT SXH 3-25, LOT E-FBO-1-35
  Reason: Shell detonation upon exiting the barrel.
  Order Date: 01.08.2024, № 370/3076
  Decision: Prohibited.

• Batch: LOT KF MKE-231-5-1989, LOT KF MKE 200-8-1985, LOT KF MKE 209-6-86, LOT SXH-12-9-55, LOT HXP 94455, LOT KF MKE-225, LOT SHX 3-24, LOT SXG 3-24
  Reason: Shell detonation upon exiting the barrel.
  Order Date: 12.08.2024, № 370/3202/dsk
  Decision: Prohibited.

Ammunition Name: MRV-U Fuze

• Batch: PDAZ-127 9153/1518
  Reason: Faulty propellant component.
  Order Date: 30.08.2024, № 370/3510/dsk
  Decision: Prohibited.

• Batch: KF MKE 234-1-1990
  Reason: Shell detonation upon exiting the barrel.
  Order Date: 10.09.2024, № 370/3644/dsk
  Decision: Prohibited.

• Batch: KF MKE 229 10-1988, KF MKE 230 1-1989, KF E-FBO-1-38-11-56
  Reason: Shell detonation upon exiting the barrel.
  Order Date: 13.09.2024, № 370/3712/dsk
  Decision: Prohibited.

• Batch: 05-SFC
  Reason: Shell detonation upon exiting the barrel.
  Order Date: 22.09.2024, № 370/3858/dsk
  Decision: Prohibited.

• Batch: JA-502-202 4-51
  Reason: Shell detonation upon exiting the barrel.
  Order Date: 23.09.2024, № 370/3880/dsk
  Decision: Prohibited.

• Batch: MKE-217
  Reason: Shell detonation upon exiting the barrel.
  Order Date: 25.09.2024, № 370/3912/dsk
  Decision: Prohibited.

• Batch: WVZ-2-5-7-55
  Reason: Shell detonation upon exiting the barrel.
  Order Date: 17.10.2024, № 370/4594/dsk
  Decision: Prohibited.

• Batch: PRD 11-19-3-56
  Reason: Shell detonation upon exiting the barrel.
  Order Date: 23.10.2024, № 370/4503/dsk
  Decision: Prohibited.

MK-PD3 – a fuze manufactured by the Indian company HFCL Limited, featuring superquick point-detonating action (SQ — Super Quick) and delayed action (DELAY).

It is used with 105 mm and 155 mm caliber projectiles. The MK-PD3 fuze ensures efficient detonation of the explosive charge upon the projectile reaching its target. It can be programmed for immediate detonation upon impact or with a delay after impact, enhancing its versatility in combat scenarios. The fuze body is made of high-quality steel, ensuring durability and reliability when used with high-velocity projectiles, even in challenging temperature conditions.

Technical Specifications

• Delay Time: 500 milliseconds.
• Required Impact Force for Detonation After Arming: ≥ 1000 g.
• Arming Distance After Firing: 100 m.
• Safe Usage at Projectile Muzzle Velocity: From 180 to 1100 m/s.
• Operating Temperature Range: -30°C to +55°C.
• Chamber Pressure Resistance: Up to 440 MPa.
• Shelf Life: At least 15 years under sealed storage conditions.
• Compliance: Meets military standards MIL-STD-1316D and STANAG 4187.
• Designed for Effective Operation at Impact Angles: From 10° to 90°.

The fuze is screwed into the projectile’s nose cavity and tightened with a wrench.

To configure the fuze:

– For point-detonating (superquick) action, use a wrench or flat-head screwdriver to turn the plunger slot to the “SQ” position. (The “SQ” position—Super Quick—is the default setting. Ensure the fuze indicator points to SQ).
– For delayed action, use a wrench or flat-head screwdriver to turn the plunger slot to the “DELAY” position.