Munitions

Mk-77 firebomb

Also known as
  • Mk-77
  • Mk77
  • Mark 77
  • Mark 77 fire bomb
  • Mk 77 fire bomb
  • Mk 77 firebomb
  • MK-77 firebomb
  • Mk 77 Mod 4
  • Mk 77 Mod 5
  • Mk77 Mod 5

The Mk-77 firebomb is a U.S. air-dropped incendiary bomb family used by Marine Corps aviation for low-altitude incendiary attack. Training references describe the later 75-gallon, roughly 520-pound firebomb as the primary U.S. firebomb, while direct public sources document Mk-77 use by coalition forces in the 1990 Gulf War and by I Marine Expeditionary Force during the 2003 Iraq invasion.

Mk-77 firebomb, Incendiary bomb, Munitions
Image source: USMC MK-77 fire bomb explodes

Role in Conflicts

Firebomb Role And Delivery

The Mk-77 is a thin-skinned fuel-gel bomb rather than a guided blast-fragmentation weapon. Marine Corps fire-support references emphasize low-altitude delivery, erratic free-fall behavior, and a broad fuel spread after impact.

ContextDocumented detailWhy it matters
Training profile75 gallons of fuel-gel mixture, about 520 lb, and a typical elliptical ground pattern around 215 ft by 75 ft.Explains why the munition is treated as an area incendiary weapon rather than a precision bomb.
Designation referencesAV-8B tables list Mod 2/4 fire bombs; later sources distinguish Mod 4 and kerosene-based Mod 5 context.Gives readers the mod structure without treating the family page as a separate variant of itself.
Desert StormMarine Corps AV-8 Harriers delivered Mk-77s primarily from low altitude against Iraqi oil-filled trenches.Links the weapon's delivery profile to a directly sourced combat role.
Operation Iraqi FreedomPublic U.S. and UK accounts describe 2003 use against enemy positions or military targets, while denying Fallujah employment.Separates confirmed 2003 Iraq War use from later disputed claims about other operations.
Profile / Specs

Profile

Origin
United States
Type
Incendiary bomb

Specifications

Mk 77 Mod 4 weight
About 520 lb
Fuel/gel mixture
75 gallons
Guidance
Unguided free-fall
Release altitude
Very low altitude
Trajectory
Erratic in flight
Typical ground pattern
Elliptical, about 215 ft long by 75 ft wide
Carrier examples
AV-8B Harrier II and F/A-18 Hornet
Carrier Aircraft

Marine Corps references connect the Mk-77 to low-altitude close-air-support aircraft, with AV-8B loadout tables and F/A-18 training media giving specific carrier examples.

CarrierCarrier typeCarriage evidence
AV-8B Harrier II, V/STOL light attack and close-air-support aircraft, Aircraft & UAVsAV-8B Harrier IIV/STOL attack aircraft

The Navy fact file lists Mk-77 Mod 2/4 fire bombs among the AV-8B's air-to-ground stores, and GlobalSecurity describes AV-8 Harriers as the primary delivery aircraft for Desert Storm Mk-77 use.

Sources: NHHC AV-8B PDF Fact File, GlobalSecurity MK-77 Fire Bomb

F/A-18 Hornet (Tactical), Carrier-capable multirole strike fighter, Aircraft & UAVsF/A-18 Hornet (Tactical)Carrier-capable strike fighter

A Marine Corps video page for a VMFA-314 live-fire exercise tags the event with F-18, Hornet, fire bomb, and Mk77 metadata.

Sources: VMFA-314 Fire Exercise Video

Timeline

Mk-77 firebomb Key Events

  1. Desert Storm fire-trench use

    Marine Corps aircraft used Mk-77 firebombs during Desert Storm, including attacks on Iraqi oil-filled fire trenches in southern Kuwait.

  2. Legacy napalm stockpile disposal

    The last filled Mk 77 Mod 4 napalm canister from the Fallbrook stockpile was destroyed in March 2001.

  3. Iraq invasion employment begins

    UK reporting on ministerial correspondence recorded 30 Mk-77 firebombs used by I Marine Expeditionary Force in Iraq between 31 March and 2 April 2003.

  4. VMFA-314 live-fire exercise

    A Marine Corps video page tags a VMFA-314 F/A-18 live-fire exercise at Twentynine Palms with Mk77, fire bomb, Hornet, and ordnance metadata.

Related Weapon Systems
GBU-43/B MOAB, GPS/INS-guided massive ordnance air blast bomb, MunitionsMunitionsGBU-43/B MOABGPS/INS-guided massive ordnance air blast bombThe GBU-43/B Massive Ordnance Air Blast, widely known as MOAB or the "Mother of All Bombs," is a very large U.S. GPS/INS-guided conventional bomb developed rapidly by the Air Force Research Laboratory with Dynetics support. It uses a BLU-120/B high-explosive body, tail and grid-fin control, and cargo-aircraft ramp deployment rather than fighter carriage. Its only documented combat use was the April 13, 2017 U.S. strike on an ISIS-K tunnel complex in Afghanistan, where commanders selected its blast effect to reduce obstacles facing Afghan and U.S. clearing forces.
Mk 118 Rockeye submunition, HEAT cluster submunition, MunitionsMunitionsMk 118 Rockeye submunitionHEAT cluster submunitionThe Mk 118 Rockeye is a U.S. high-explosive anti-tank submunition carried in Rockeye-family cluster bombs, including Mk 20, CBU-99, and CBU-100 configurations that release 247 bomblets over an area target. Its shaped-charge warhead and folding fins made it an anti-armor bomblet, while failed functioning creates unexploded-ordnance hazards after a strike. The submunition is documented through Rockeye use in Vietnam, the Gulf War, Kosovo, the 2003 Iraq War, and North Sinai, where Amnesty International linked an unexploded Mk 118 to Egyptian Air Force cluster-munition use during Operation Sinai 2018.
Molotov cocktails, Hand-thrown improvised incendiary weapon, MunitionsMunitionsMolotov cocktailsHand-thrown improvised incendiary weaponMolotov cocktails are hand-thrown improvised incendiary weapons built around a breakable container and ignition source, but wartime examples range from ad hoc bottles to semi-standardized military incendiary grenades. The cataloged conflict record now spans U.S. Marine use during Fallujah house-clearing in the 2003 Iraq War, IS-aligned militant use against Philippine troops in Marawi, and Ukrainian volunteer production and distribution during the 2022 full-scale Russian invasion.

Sources

NHHC AV-8B PDF Fact FilePublisher: Naval History and Heritage Command | Note: Supports the AV-8B Harrier II air-to-ground stores list that includes Mk-77 (Mod 2/4) fire bombs. | Accessed: 2026-06-29Principles of Fire SupportPublisher: U.S. Marine Corps Training Command | Note: Supports the Mk-77 Firebomb as the primary firebomb, the 75-gallon fuel/gel load, the 520 lb weight figure, and typical ground-pattern dimensions. | Accessed: 2026-06-29USMC MK-77 fire bomb explodesPublisher: U.S. Marine Corps | Note: Supports image provenance for the public-domain Mk-77 fire bomb photograph. | Accessed: 2026-06-29GlobalSecurity MK-77 Fire BombPublisher: GlobalSecurity.org | Note: Supports Mk-77 family background, 1990 Gulf War direct use by Marine Corps aircraft, Mod 4/Mod 5 context, low-altitude AV-8 Harrier delivery, and Operation Iraqi Freedom preparation details. | Accessed: 2026-06-29USINFO Fallujah Illegal Weapons ResponsePublisher: U.S. Department of State International Information Programs via GlobalSecurity.org | Note: Supports 2003 Iraq War direct-use context by stating that Mark-77 firebombs were used against enemy positions in 2003 while distinguishing that use from Fallujah allegations. | Accessed: 2026-06-29Guardian Iraq Fire BombsPublisher: The Guardian | Note: Supports 2003 Iraq War direct-use details from UK ministerial correspondence, including the reported 30 Mark 77 fire bombs used by U.S. Marines from 31 March to 2 April 2003. | Accessed: 2026-06-29FY2006 Navy Ammunition BudgetPublisher: Department of the Navy | Note: Supports mid-2000s Mk 77 procurement quantities, training/war-reserve rationale, and Triumph, Inc. as a documented Mk 77 bombs contractor for FY2003-FY2004 buys. | Accessed: 2026-06-29VMFA-314 Fire Exercise VideoPublisher: U.S. Marine Corps | Note: Supports a 2019 VMFA-314 live-fire training context tagged with F-18, Hornet, fire bomb, Mk77, and ordnance metadata. | Accessed: 2026-06-29