Artillery

155mm M59 Long Tom

Also known as
  • M59 Long Tom
  • 155 mm Gun M1
  • 155 mm Gun M1A1
  • 155 mm Gun M2
  • M1 Long Tom
  • M2 Long Tom
  • Long Tom 155mm gun

The 155mm M59 Long Tom was the postwar designation for the U.S. M1/M1A1/M2 long-range 155 mm field gun family. Built around a 45-caliber tube, split-trail carriage, and tractor-towed mobility, it served as Allied heavy artillery in the Second World War and remained a legacy U.S. heavy gun into the Vietnam War era.

155mm M59 Long Tom, 155 mm towed field gun, Artillery
Image source: British Long Tom Italy Image

Role in Conflicts

Second World War
Fire SupportLong-Range Strike
Side
Allied Powers

U.S. Army and Marine Corps histories document Long Tom 155 mm guns supporting Allied operations in Sicily and the Central Solomons, including Troina fire support and 9th Defense Battalion fires against Munda targets.

1955 Vietnam War
Fire Support
Side
United States and South Vietnam

WeaponSystems.net identifies the M59 Long Tom as a postwar redesignation of the wartime 155 mm Gun M1 family and states that the type was also used in the Vietnam War before newer self-propelled heavy artillery supplemented it.

Profile / Specs

Profile

Origin
United States
Type
155 mm towed field gun
Service note
Second World War and Cold War service
Designer
U.S. Army Ordnance Department
Designed
Interwar development; standardized as the 155 mm Gun M1 in 1938
Produced
1940-1945
Number built
About 1,880 to 1,882 guns reported in open references

Specifications

Caliber
155 mm
Gun type
45-caliber rifled towed field gun
Crew
14 in WeaponSystems.net; 15 for the Marine Corps M1A1 sidebar
Travel weight
About 13.9 t / 30,600 lb
Barrel length
6.97 m
Maximum range
23.7 km / about 14.7 mi
Muzzle velocity
853 m/s / 2,799 ft/s
Rate of fire
About 40 rounds per hour in WeaponSystems.net; one to three rounds per minute in Marine Corps staff-ride material
Elevation
-2 to +65 degrees
Traverse
60 degrees total
Carriage
Eight-wheel twin-axle split-trail carriage with two-wheel limber
Towing vehicles
Mack NO 6x6 truck and M4 High Speed Tractor listed as wartime prime movers
Design And Field Handling

The Long Tom traded hand mobility for range and shell weight. Its eight-wheel split-trail carriage, retracting travel arrangement, and tractor requirement made it a corps-level heavy gun rather than a light divisional howitzer.

Gun class

Long 155 mm field gun with a 45-caliber tube and no muzzle brake.

WeaponSystems.net distinguishes it from shorter-range howitzers by its flatter trajectory and range-focused design.

Mobility limit

Too heavy for manual movement in the field; moved by tractors such as the Mack NO or M4 High Speed Tractor.

The Marine Corps history also describes tractor movement and a combined crew of 15 for the M1A1 gun.

Postwar name

M59 refers to the redesignated M1/M1A1/M2 Long Tom family after the Second World War.

This record keeps the M59 title because that is the launcher-provided target model name.

Sources: WeaponSystems.net M59 Long Tom; Up the Slot Long Tom Sidebar; Okinawa Staff Ride Long Tom Specifications.

Watervliet Production Context

Watervliet Arsenal was not the only wartime industrial actor behind U.S. cannon production, but National Historic Landmark documentation makes it a directly sourced manufacturer for this record. The nomination describes Watervliet as the Army's only manufacturing plant for guns of 155 mm and larger during the Second World War and names the Long Tom as the most important of its large mobile artillery pieces in 1943.

Production role

Army cannon manufacturing and coordination center for large guns.

Documented system

155 mm cannon nicknamed Long Tom, described as a towed weapon with roughly 14-mile reach.

Source: Watervliet Arsenal NHL Nomination.

Variants

M59 is the later U.S. designation applied to the M1/M1A1/M2 Long Tom gun family rather than a clean-sheet postwar design.

VariantConfigurationDesignation notes
155 mm Gun M1Initial standardized Long Tom model

WeaponSystems.net lists the 1938 M1 as the early production model and notes that only 20 were produced.

Sources: WeaponSystems.net M59 Long Tom

155 mm Gun M1A1Main wartime production designation

The Marine Corps history sidebar identifies the M1A1 155 mm gun as the mobile Long Tom used by defense and corps artillery battalions.

Sources: Up the Slot Long Tom Sidebar

155 mm Gun M2Late wartime gun variant

WeaponSystems.net describes the M2 as a 1945 improved model with a modified breech ring.

Sources: WeaponSystems.net M59 Long Tom

M59Post-Second World War redesignation

WeaponSystems.net states that the M59 designation was applied after the war to the M1, M1A1, and M2 models.

Sources: WeaponSystems.net M59 Long Tom

Timeline

155mm M59 Long Tom Key Events

  1. 155 mm Gun M1 standardized

    The Long Tom family entered U.S. service as the 155 mm Gun M1 before wartime mass production and later M1A1/M2 variants.

    Sources: WeaponSystems.net M59 Long Tom

  2. 9th Defense Battalion fires at Munda

    During the Central Solomons campaign, Battery A of the 9th Defense Battalion was in firing position on Rendova and began shelling Japanese positions around Munda.

    Sources: Up the Slot Long Tom Sidebar

  3. Long Toms support the Battle of Troina

    The U.S. Army Center of Military History's Sicily booklet identifies a battalion of 155 mm Long Tom guns among the artillery massed for the battle at Troina.

    Sources: U.S. Army Sicily Campaign Booklet

  4. British Long Tom photographed in Italy

    Imperial War Museums imagery preserved on Wikimedia Commons shows an American-built 155 mm Long Tom of 33/61 Heavy Regiment, Royal Artillery, at Vergato, Italy.

    Sources: British Long Tom Italy Image

Media

155mm M59 Long Tom Videos

155mm M59 Long Tom Images

155mm M59 Long Tom, 155 mm towed field gun, Artillery - view 1
Source: Long Tom England Training Image
Related Weapon Systems
M109, 155 mm tracked self-propelled howitzer family, ArtilleryArtilleryM109155 mm tracked self-propelled howitzer familyThe M109 is a U.S.-origin 155 mm tracked self-propelled howitzer family built for mobile indirect fire with armored and mechanized forces. The family spans the original short-tube vehicle, M109A1 to M109A4 rebuild and export lines, the M109A5 M284-cannon upgrade, the digitally modernized M109A6 Paladin, current M109A7 production, and the longer-barrel M109-52 concept; catalog evidence here centers on direct conflict use by U.S., Ukrainian, U.S.-led coalition, and Israeli forces.
M198 155 mm howitzer, 155 mm towed howitzer, ArtilleryArtilleryM198 155 mm howitzer155 mm towed howitzerThe M198 is a U.S.-designed 155 mm towed howitzer developed at Rock Island Arsenal to replace older M114-series guns. Its split-trail carriage, nine-person crew, air-transportable layout, and 22-30 km range made it a standard U.S. Army and Marine Corps fire-support weapon before the lighter M777 replaced it in U.S. service. Direct conflict sourcing now traces M198 fielding from Desert Storm through U.S. use in Afghanistan and Iraq, Islamic State capture and cross-border use in Iraq and Syria, Iraq-aligned militia firing, and coalition-backed Iraqi Army live-fire training.

Sources

WeaponSystems.net M59 Long TomPublisher: WeaponSystems.net | Note: Supports M59 identity, postwar redesignation, variants, specifications, mobility, and direct 1955 Vietnam War use statement. | Accessed: 2026-07-06Up the Slot Long Tom SidebarPublisher: National Park Service / U.S. Marine Corps historical text | Note: Supports Second World War direct use by the 9th Defense Battalion in the Central Solomons, M1A1 Long Tom service, crew and mobility details, and Munda fire-support context. | Accessed: 2026-07-06U.S. Army Sicily Campaign BookletPublisher: U.S. Army Center of Military History | Note: Supports Second World War direct use by identifying 155 mm Long Tom guns and batteries among Allied artillery supporting the Battle of Troina in Sicily. | Accessed: 2026-07-06Okinawa Staff Ride Long Tom SpecificationsPublisher: Marine Corps University | Note: Supports Long Tom specifications including weight, crew, traverse, elevation, muzzle velocity, range, ammunition categories, and one-to-three-rounds-per-minute rate of fire. | Accessed: 2026-07-06Watervliet Arsenal NHL NominationPublisher: U.S. Department of Defense DENIX / National Park Service | Note: Supports Watervliet Arsenal manufacturer context and its Second World War production of large mobile artillery, including the 155 mm Long Tom. | Accessed: 2026-07-06British Long Tom Italy ImagePublisher: Wikimedia Commons | Note: Supports Second World War direct fielded-by evidence by showing an American-built 155 mm Long Tom of 33/61 Heavy Regiment, Royal Artillery, at Vergato, Italy, on 1945-02-22; also supports image provenance. | Accessed: 2026-07-06Long Tom England Training ImagePublisher: Wikimedia Commons | Note: Public-domain image used as a secondary gallery item showing 155 mm Long Tom artillery units training in England during the Second World War. | Accessed: 2026-07-06