US M888 60mm HE Mortar

1. Overview

The M888 is a United States 60mm high-explosive (HE) mortar cartridge designed for the M224 Lightweight Company Mortar System (LWCMS). While sharing the same projectile body as the M720, the M888 utilizes the simpler and less expensive M935 point-detonating fuze rather than the sophisticated M734 multi-option fuze, making it a cost-effective option for training and combat operations where the advanced fuze capabilities are not required. The M888 provides fragmentation and blast effects identical to the M720, offering impact and delay function modes through its M935 fuze. It represents the standard point-detonating HE option in the M224 ammunition family.

2. Country/Bloc of Origin

  • Country: United States of America
  • Development Period: Mid-1980s
  • Type Classification Date: 1986
  • Manufacturers: American Ordnance LLC (Iowa and Milan Army Ammunition Plants) and other contractors
  • Service Entry: Late 1980s with M224 LWCMS

3. Ordnance Class

  • Type: Mortar Cartridge, High-Explosive (HE)
  • Primary Role: Anti-personnel and light materiel engagement through fragmentation and blast effects
  • Delivery Method: Muzzle-loaded, fin-stabilized mortar projectile
  • Classification: Standard A ammunition for M224 LWCMS

4. Ordnance Family / Nomenclature

  • Official Designation: Cartridge, 60mm HE, M888
  • Related Variants:
    • M720: Same projectile body with M734 multi-option fuze
    • M720A1: IM-compliant version with M734A1 fuze and PAX-21 fill
    • M768: Lower-cost training HE with M783 PD fuze and IM features
  • Relationship to M720: The M720 and M888 are identical except for fuzing
  • Compatible Weapon Systems:
    • M224 60mm Lightweight Company Mortar System (primary)
    • M224A1 60mm Mortar
    • M19 60mm Mortar (at reduced charges)
  • Unit Cost: Approximately $67 (FY2002)—significantly less than M720’s ~$497

5. Hazards

Primary Hazards

  • Blast: High-explosive detonation produces significant overpressure
  • Fragmentation: High-fragmentation steel body produces numerous lethal fragments
  • Effective Casualty Radius: Approximately 20–30 meters
  • Lethal Radius: Approximately 10–15 meters

Fuze Hazards

  • Impact Mode (Superquick): Detonates on ground contact
  • Delay Mode: Detonates 0.5 seconds after impact
  • Safety Wire: M935 fuze has a pull-wire safety that must be removed before firing

Sensitivity Considerations

  • Armed Fuze: Once safety wire is removed and round is fired, fuze is extremely sensitive to impact
  • Handling: Rounds with safety wires removed should never be returned to packaging
  • Dud Potential: Point-detonating fuzes may fail on soft ground, water, or oblique impact

UXO Considerations

  • Fuze State: Unexploded rounds likely have armed fuzes (safety wire removed during firing preparation)
  • Impact Sensitivity: M935 PD fuze in armed state is sensitive to disturbance
  • Explosive Condition: Composition B fill is stable but hazardous
  • Environmental Degradation: Corrosion may affect fuze function unpredictably

Special Hazards

  • The M935 fuze’s delay mode is designed to allow penetration into structures or bunkers before detonation
  • Delayed-fuse rounds that fail to detonate present extreme hazard

6. Key Identification Features

Dimensions

  • Caliber: 60mm
  • Overall Length: Approximately 381mm (15 inches)
  • Body Diameter: 60mm nominal
  • Complete Round Weight: Similar to M720 (~1.68 kg / 3.7 lbs)
  • Explosive Filler Weight: 0.79 lbs (0.36 kg)

Physical Characteristics

  • Body Construction: AISI 1340 alloy steel, high-fragmentation design
  • Body Shape: Streamlined ogive configuration identical to M720
  • Fin Assembly: M27 aluminum alloy fin and tail boom assembly with obturating ring
  • Fuze: M935 point-detonating fuze (visually distinct from M734)

Color and Markings

  • Body Color: Olive drab (OD green)
  • Marking Color: Yellow stenciling indicating HE content
  • Typical Markings:
    • “60MM M888” (designation)
    • Lot number and date
    • Manufacturer code
    • “COMP B” explosive fill indication

Distinctive Features

  • M935 PD Fuze: Smaller, simpler fuze body compared to the large M734 multi-option fuze
  • Fuze Safety Wire: Visible pull-wire safety with red streamer
  • Setting Options: Simple SQ/D (Superquick/Delay) switch rather than four-position dial
  • Identical Body: Same projectile body as M720—differentiation is by fuze

7. Fuzing Mechanisms

Primary Fuze: M935 Point-Detonating Fuze

The M935 is a conventional point-detonating fuze offering impact (superquick) and delay function modes.

Fuze Settings

  1. Superquick (SQ): Detonates immediately on impact
    • Standard impact function
    • Effective against personnel in the open
  2. Delay (D): Detonates 0.5 seconds after impact
    • Allows penetration before detonation
    • Effective against structures, bunkers, and fortifications

Fuze Components

  • Striker: Inertia-driven firing pin
  • Detonator: Primary explosive charge
  • Booster: RDX or tetryl charge
  • Delay Element: Pyrotechnic delay train (engaged in D mode)
  • Safety Wire: Pull-wire safety with red streamer

Arming Sequence

  1. Pre-Launch: Safety wire in place prevents striker movement
  2. Preparation: Safety wire removed immediately before firing
  3. Launch: Setback force initiates arming sequence
  4. Flight: Fuze completes arming
  5. Impact: Striker initiates detonator (SQ) or delay train (D)

Safety Wire Handling

  • Safety wire must be removed immediately before firing
  • If round is not fired, safety wire should be reinserted
  • Rounds with missing safety wires must not be stored or returned to ammunition supply

8. History of Development and Use

Development Background

The M888 was developed concurrently with the M720 to provide a lower-cost HE option for the M224 system. While the M734 multi-option fuze represented a significant technological advancement, its complexity and cost made it impractical for many training and routine combat applications. The M888 offers the same terminal effects at a fraction of the cost.

Design Philosophy

  • Shared Body: Using the identical projectile body as the M720 simplified logistics and training
  • Cost Reduction: The M935 PD fuze costs significantly less than the M734 multi-option fuze
  • Adequate Capability: For many missions, simple impact or delay function is sufficient
  • Training Economy: Allows realistic training without expending expensive multi-option rounds

Type Classification

  • 1986: M888 type classified alongside M720

Cost Comparison

  • M720 with M734 fuze: ~$497 (FY2005)
  • M720A1 with M734A1 fuze: ~$489 (FY2005)
  • M888 with M935 fuze: ~$67 (FY2002)
  • M768 with M783 fuze: ~$353 (FY2005)

Tactical Employment

The M888 is employed identically to the M720 for missions not requiring proximity or near-surface burst:

Standard Combat Use

  • Impact detonation against personnel and light materiel
  • Delay detonation for penetration of light structures and field fortifications
  • Area suppression and neutralization

Training

  • Full-range live-fire training
  • Fire mission execution practice
  • New gunner qualification

Combat Use

  • Desert Storm (1991): Combat employment
  • Afghanistan (2001–2021): Extensive use in training and combat
  • Iraq (2003–2011): Combat operations
  • Global War on Terror: Continuing service

Relationship to M720 in Combat Loads

Typical combat loads combine M720 (or M720A1) and M888 rounds:

  • M720/M720A1 for missions requiring proximity or near-surface burst
  • M888 for standard impact missions
  • Mix ratio varies by mission requirements and ammunition availability

9. Technical Specifications

SpecificationValue
Caliber60mm
Overall Length~381mm (15 in)
Body Diameter60mm
Complete Round WeightSimilar to M720
Body MaterialAISI 1340 alloy steel
Explosive FillComposition B
Filler Weight0.79 lbs (0.36 kg)
FuzePoint-Detonating, M935
Fuze ModesSuperquick (SQ), Delay (D)
Delay Time0.5 seconds
PropellantM204 (4 increments)
PrimerPercussion, M35
Ignition CartridgeM702
Maximum Range3,490 m
Minimum Range70 m
Rate of Fire (Max)30 rounds/min
Rate of Fire (Sustained)15 rounds/min
Unit Cost~$67 (FY2002)

10. Frequently Asked Questions

Q: What is the difference between the M888 and M720? A: The M888 and M720 use the identical projectile body, explosive fill, and fin assembly. The only difference is the fuze: the M720 uses the M734 multi-option fuze (proximity/near-surface burst/impact/delay), while the M888 uses the M935 point-detonating fuze (superquick/delay only). This makes the M888 significantly less expensive (~$67 vs. ~$497) while maintaining identical terminal effects for impact missions.

Q: When should the M720 be used instead of the M888? A: The M720 should be used when proximity or near-surface burst is required—typically for engaging personnel in the open where airburst maximizes fragment dispersion. For standard impact missions against fortifications, structures, or when simple impact/delay is sufficient, the M888 provides equivalent lethality at lower cost.

Q: What does the safety wire on the M935 fuze do? A: The safety wire physically blocks the striker assembly, preventing fuze function even if the round experiences impact. It must be removed immediately before firing. If a round is prepared for firing but not used, the safety wire must be reinserted. Rounds with safety wires removed should never be returned to storage or shipping containers.

Q: What is the delay time for the M935 fuze in delay mode? A: The M935 provides a 0.5-second delay between impact and detonation when set to D (Delay) mode. This allows the round to penetrate light structures, bunkers, or fortifications before detonating, maximizing damage to interior spaces and personnel within.

Q: Can the M888 be fired in handheld mode? A: Yes, but with charge limitations identical to the M720. When firing the M224 in handheld mode (without bipod/baseplate), the M888 is limited to charge 1 maximum. Higher charges generate excessive recoil that cannot be safely controlled in handheld configuration.

Q: Why isn’t there an M888A1 with IM-compliant features? A: The IM-compliant development effort focused primarily on the M720A1 with its M734A1 multi-option fuze, as the M720 series is the preferred combat round. The M768 serves as the IM-compliant point-detonating option with M783 PD fuze and PAX-21 explosive fill. The M768 fills the role that an “M888A1” would serve, though at higher cost than the original M888.

Q: What are the UXO considerations for M888 rounds? A: The M935 PD fuze may fail to function on soft ground, mud, water, or oblique impact angles. Unexploded M888 rounds will have armed fuzes (safety wire removed during preparation) that may be extremely sensitive to disturbance. The 0.5-second delay mode means some rounds may have initiated the delay train before failing, creating additional unpredictability. Never approach, handle, or disturb suspected UXO.

Safety Notice

⚠️ All ordnance should be considered dangerous until verified safe by qualified EOD personnel.

This information is for educational and identification purposes only

Never handle, move, or disturb suspected UXO

M935 fuzes without safety wires are armed and impact-sensitive

Delay-mode duds may have initiated delay elements creating extreme unpredictability

Establish a safe perimeter and mark the location

Report findings to military or law enforcement authorities immediately