US M68 Directional Anti-Personnel Mine

Overview

The M68 is a United States-designed directional fragmentation anti-personnel mine developed as part of the Area Denial Artillery Munition (ADAM) system. Unlike conventionally emplaced directional mines such as the M18 Claymore, the M68 is artillery-delivered, designed to be dispensed from 155mm artillery projectiles. This enables rapid remote deployment of minefields without requiring personnel to enter the target area. The M68 represents a significant advancement in the concept of scatterable mines, combining directional lethality with stand-off delivery capability.

Country/Bloc of Origin

  • Country of Origin: United States of America
  • Development Period: 1970s-1980s
  • Military Branch: U.S. Army
  • Development Program: Part of the broader Family of Scatterable Mines (FASCAM) program
  • Primary Contractor: Multiple defense contractors involved in ADAM system development
  • NATO Adoption: Primarily U.S. system; interoperability considerations with NATO allies

Ordnance Class

  • Type: Anti-Personnel Mine
  • Subtype: Directional fragmentation mine
  • Delivery Category: Scatterable mine (artillery-delivered)
  • Primary Role: Area denial, remote minefield emplacement, disruption of enemy movement
  • Delivery Method: Dispensed from 155mm M692/M731 ADAM artillery projectiles
  • Activation Type: Tripwire-initiated (deployed tripwires after landing)

Ordnance Family/Nomenclature

  • Official Designation: M68 Anti-Personnel Mine
  • System Designation: Component of ADAM (Area Denial Artillery Munition)
  • Carrier Projectiles:
    • M692: 155mm projectile containing M68 mines with short self-destruct time
    • M731: 155mm projectile containing M68 mines with long self-destruct time
  • Related Munitions:
    • M67: Anti-tank mine component of ADAM system
    • M86 PDM: Pursuit Deterrent Munition (different AP mine concept)
    • M18A1 Claymore: Conventionally emplaced directional mine (predecessor concept)
  • FASCAM Family: Part of Family of Scatterable Mines program alongside ground-delivered and air-delivered systems
  • NSN: Various national stock numbers assigned based on packaging configuration

Hazards

Primary Hazards
  • Fragmentation: Primary kill mechanism; projects fragments in a directional pattern
  • Blast: Secondary effect from explosive charge
  • Tripwire Network: Seven liquid tripwire filaments create activation zone
Sensitivity Considerations
  • Tripwire Sensitivity: Liquid filaments break easily upon contact, initiating detonation
  • Orientation Sensitivity: Mine must orient correctly during deployment for directional effect
  • Self-Destruct Mechanism: Contains pyrotechnic self-destruct/self-neutralization feature
  • Battery-Powered: Internal lithium battery powers arming and self-destruct systems
Danger Areas
  • Lethal Zone: Directional; approximately 60-degree arc in front of mine face
  • Effective Range: Up to 30 meters (100 feet) in primary direction
  • Backblast Hazard: Reduced compared to frontal zone but still dangerous
  • Tripwire Radius: Seven filaments extend approximately 6 meters (20 feet) from mine
Self-Destruct/Self-Neutralization
  • Short SD Time (M692): Approximately 4 hours
  • Long SD Time (M731): Approximately 48 hours
  • Self-Neutralization Backup: If self-destruct fails, battery depletion renders mine inert
  • Reliability Caveat: Self-destruct is not 100% reliable; UXO hazard remains
UXO Considerations
  • Mines that fail to self-destruct remain armed and dangerous
  • Battery failure does not guarantee safe condition
  • Tripwires may remain taut and functional
  • Environmental factors can affect self-destruct reliability
  • Never assume scatterable mines have self-destructed; treat as live ordnance

Key Identification Features

Physical Dimensions
  • Length: Approximately 76mm (3 inches)
  • Width: Approximately 57mm (2.25 inches)
  • Height: Approximately 32mm (1.25 inches)
  • Weight: Approximately 200g (7 oz)
Shape and Profile
  • Rectangular/wedge-shaped body
  • Directional face angled for fragment projection
  • Compact profile designed for artillery dispensing
  • Tripwire deployment mechanism visible as filament spools
Color and Markings
  • Body Color: Olive drab or green
  • Markings:
    • “M68” designation
    • Lot number and date of manufacture
    • Directional indicators (FRONT/FACE TOWARD ENEMY)
    • Yellow band or markings may indicate live HE content
  • Warning Labels: Hazard markings per military standards
Material Composition
  • Body: Plastic/polymer casing
  • Fragmentation Layer: Steel balls or pre-formed fragments embedded in explosive matrix
  • Internal Components: Lithium battery, electronic arming circuit, detonator
Distinctive Features
  • Wedge or curved directional face
  • Seven tripwire filament deployment tubes
  • Compact, artillery-dispensable profile
  • Electronic component housing
  • Liquid (optical) tripwire filaments (clear, difficult to see)
  • Stabilization features for correct landing orientation

Fuzing Mechanisms

Fuze Type
  • Electronic Fuze: Battery-powered electronic arming and firing circuit
  • Tripwire Activation: Liquid-filled filament break-wire system
Arming Sequence
  1. Mine is ejected from carrier projectile during flight
  2. Ribbon/parachute system slows descent and orients mine
  3. Mine impacts ground; begins arming sequence
  4. Electronic timer initiates arming delay (typically seconds to minutes)
  5. Seven tripwire filaments deploy, extending outward from mine
  6. Self-destruct timer begins countdown
  7. Mine is now armed and sensitive to tripwire disturbance
Tripwire System
  • Number of Tripwires: Seven liquid-filled filaments
  • Deployment Range: Approximately 6 meters (20 feet) from mine body
  • Activation Mechanism: Breaking filament interrupts optical/electrical circuit, triggering detonation
  • Filament Characteristics: Thin, clear, difficult to detect visually
Safety Features
  • Arming delay prevents premature detonation during deployment
  • Safe-separation distance from delivery aircraft/artillery piece
  • Self-destruct/self-neutralization reduces long-term hazard (in theory)
Self-Destruct Mechanism
  • Pyrotechnic self-destruct initiates at programmed time
  • Battery powers timing circuit
  • Backup self-neutralization occurs when battery depletes
  • Critical Note: Self-destruct is not 100% reliable; unexploded mines remain dangerous
Anti-Handling Devices
  • Not specifically designed with anti-handling features
  • However, any movement of armed mine risks tripwire activation
  • Attempting to disarm or move mine is extremely hazardous

History of Development and Use

Development Background

The M68 emerged from U.S. Army requirements in the 1970s for rapidly emplaced minefields that did not require soldiers to manually place each mine. The concept of scatterable mines addressed tactical needs for:

  • Responsive minefield emplacement
  • Reduced exposure of personnel to enemy fire
  • Ability to deny terrain at extended ranges
  • Battlefield shaping without advance positioning
FASCAM Program

The Family of Scatterable Mines (FASCAM) program developed multiple delivery systems for scatterable mines:

  • Artillery-delivered (ADAM/RAAM)
  • Ground-dispensed (Volcano, MOPMS)
  • Air-delivered (Gator, CBU-89)

The M68 became the anti-personnel component of the ADAM artillery system.

Design Innovation

The M68’s directional fragmentation concept applied M18 Claymore principles to a scatterable format. Key innovations included:

  • Miniaturization for artillery dispensing
  • Self-orienting deployment mechanism
  • Liquid tripwire technology
  • Electronic self-destruct with battery backup
Service History
  • Initial Fielding: 1980s with U.S. Army artillery units
  • Operational Use: Persian Gulf War (1991), potentially other conflicts
  • Training Use: Extensively used in exercises to demonstrate FASCAM concepts
Tactical Employment

ADAM mines were intended for:

  • Disrupting enemy follow-on forces
  • Protecting flanks and gaps
  • Delaying enemy maneuver
  • Creating hasty protective minefields
  • Shaping enemy movement into engagement areas
Current Status
  • Production: Limited; U.S. landmine policy has restricted procurement and use
  • U.S. Policy Evolution: Various policy changes have affected scatterable mine programs
  • Stockpiles: Maintained but subject to policy restrictions
  • Ottawa Treaty: United States is not a signatory but has implemented policy restrictions on persistent mines
Controversy and Policy

Scatterable mines with self-destruct features were developed partly to address humanitarian concerns about persistent minefields. However:

  • Self-destruct reliability is not 100%
  • Mines that fail to function as designed create UXO hazards
  • International humanitarian law debates continue regarding scatterable mines
  • U.S. policy has fluctuated regarding use and procurement

Technical Specifications

SpecificationValue
Total WeightApproximately 200g (7 oz)
Dimensions76mm x 57mm x 32mm (3″ x 2.25″ x 1.25″)
Explosive FillComposition A5 or similar
Explosive WeightApproximately 21g (0.74 oz)
Fragment TypeSteel balls or pre-formed fragments
Fragment CountApproximately 1,000+ small fragments
Effective RangeUp to 30 meters (100 feet) directional
Tripwire CountSeven liquid filaments
Tripwire LengthApproximately 6 meters (20 feet) each
Arming TimeVariable (seconds to minutes after deployment)
Self-Destruct Time4 hours (M692) or 48 hours (M731)
Power SourceLithium battery
Operating Temperature-37°C to +63°C (-35°F to +145°F)
Carrier Projectile155mm M692/M731 ADAM
Mines per Projectile36 M68 mines per round

Frequently Asked Questions

Q: How does the M68 differ from the M18A1 Claymore mine? A: While both are U.S. directional fragmentation anti-personnel mines, they differ significantly in delivery and employment. The M18A1 Claymore is hand-emplaced by soldiers, electrically command-detonated (or tripwire-activated in defensive mode), and weighs approximately 1.6 kg. The M68 is artillery-delivered in large numbers, automatically deploys tripwires upon landing, uses electronic self-destruct, and weighs only about 200g. The M68 sacrifices the M18A1’s larger payload for the ability to rapidly emplace remote minefields without exposing personnel.

Q: What makes the M68’s tripwire system unique? A: The M68 uses seven liquid-filled optical filament tripwires that automatically deploy after the mine lands. These filaments are extremely thin and clear, making them very difficult to detect visually. When a filament breaks, it interrupts an optical or electrical circuit that triggers detonation. This system allows automatic minefield arming without soldier involvement and creates a substantial activation zone around each mine.

Q: How reliable is the self-destruct mechanism? A: The M68’s self-destruct/self-neutralization system was designed to reduce the long-term humanitarian hazard of scatterable mines. However, no self-destruct mechanism is 100% reliable. Factors affecting reliability include battery condition, electronic component function, environmental extremes, and physical damage during deployment. Military specifications typically require high reliability percentages, but even small failure rates across large numbers of deployed mines result in significant UXO hazards. For this reason, all scatterable mines should be treated as potentially live until confirmed safe by EOD personnel.

Q: How many M68 mines are delivered in a single artillery round? A: A single 155mm ADAM projectile (M692 or M731) contains 36 M68 anti-personnel mines. The projectile ejects its payload at a predetermined point in flight, dispersing mines across the target area. A battery of artillery firing multiple ADAM rounds can rapidly create a minefield of hundreds of mines. This density is intended to provide effective area denial while accounting for mines that may malfunction or land in ineffective positions.

Q: What determines whether M692 or M731 projectiles are used? A: The choice between M692 (short self-destruct) and M731 (long self-destruct) depends on tactical requirements. The M692’s 4-hour self-destruct time is appropriate for brief denial missions where friendly forces may need to transit the area soon. The M731’s 48-hour window provides extended denial for longer operations. Commanders select the projectile type based on the mission’s time requirements and the anticipated need for friendly force freedom of movement through the mined area.

Q: Can the M68 function if it lands in an unfavorable orientation? A: The M68 includes design features to promote correct orientation during deployment, including stabilization systems during descent. However, mines that land inverted, on their side, or in obstructed positions may have reduced effectiveness or may fail to function as designed. Directional mines depend on correct orientation for their fragment pattern to engage targets effectively. Mines in poor orientations may still pose UXO hazards even if their directional lethality is compromised.

Q: What is the relationship between the M68 and M67 in the ADAM system? A: The ADAM system includes both anti-personnel (M68) and anti-tank (M67) mine components. The M67 is a magnetically-fuzed anti-tank mine designed to attack the underbelly of vehicles. Both mine types may be delivered in the same operational context to create mixed minefields that threaten both personnel and vehicles. However, they are carried in separate projectile types—the M692/M731 contain M68 AP mines, while M718/M741 projectiles contain M67 AT mines.

Q: How should the M68 be approached if encountered as UXO? A: If an M68 is encountered, assume it is armed and dangerous regardless of how much time has passed since deployment. Do not approach; the tripwire filaments are nearly invisible and extend approximately 6 meters from the mine. Do not attempt to cut tripwires or move the mine. Mark the area from a safe distance, withdraw carefully, and report to qualified EOD personnel. The mine’s small size and low profile may make it difficult to spot; be alert for tripwire filaments as the first indication of presence.

SAFETY NOTICE: This lesson is intended for educational purposes in support of EOD training, humanitarian demining operations, and military ordnance recognition. All ordnance should be treated as dangerous until rendered safe by qualified personnel.