Canon de 155 GPF mle.1917
155 mm GPF gun in travel position at US Army Ordnance Museum
Type	Field gun, Coastal artillery
Place of origin	France
Service history
In service	1917–1945
Used by	France Australia Brazil Chile Finland Nazi Germany Royal Italian Army Imperial Japan Philippines Free Poland United States
Wars	World War I World War II
Production history
Designer	Colonel Louis Filloux
Manufacturer	Renault Atelier de Bourges Atelier de Puteaux
Specifications
Mass	Travel: 13,000 kg (28,660 lbs)
Barrel length	5.915 m (20 ft) L/38.2
Shell	separate-loading, cased charge. 43 kg (95 lb)
Caliber	155 mm (6.10 in)
Recoil	1.8m 10° to 1.1 28°
Carriage	split trail
Elevation	0° to +35°
Traverse	60°
Rate of fire	2 rounds per minute
Muzzle velocity	735 m/s (2,411 ft/s)
Maximum firing range	19,500 m (21,325 yds)

The Canon de 155 Grande Puissance Filloux (GPF) modèle 1917 was a WWI-era French-designed 155 mm gun used by the French Army and the United States Army during the first half of the 20th century in towed and self-propelled mountings.

The gun was designed during the First World War by Colonel Louis Filloux to meet an urgent need for modern heavy artillery and became the standard heavy field gun of the French Army from 1917 until the Second World War. It was also adopted by the United States as the M1917 and a close derivative of it was made in and used by the US as the M1918 through the Second World War.^{[citation needed]}

The design adopted the split trail invented by French Colonel Deport in the early 1910s (see Cannone da 75/27 modello 11), and unlike the previous pieces, which had their carriages riveted from machined and/or pressed steel parts, utilized very large steel castings.^{[citation needed]}

The gun was also manufactured in the United States from 1917, after the US switched to metric artillery based on French patterns. The castings became the main technological difficulty, with the work done by the Minneapolis Steel & Machinery Company.^[1]

It was used by the United States Army and United States Marine Corps as their primary heavy gun as the 155 mm Gun M1917 (French-made) or M1918 (US-made) until 1942, when it was gradually replaced by the 155 mm M1A1 Long Tom. US Army forces in the Far East (USAFFE), including the 301st FA Regiment (Philippine Army), the 86th FA Regiment (Philippine Scouts) and also US Coast Artillery units (91st and 92nd CA Regiments, Philippine Scouts), used this gun against the Japanese in the Philippines campaign (1941–1942). Some of the guns were originally emplaced in "Panama mounts" on Corregidor, Caballo and Carabao islands at the entrance of Manila Bay. Some guns were dismounted and used as roving batteries and gave effective counter-battery fire. The gun was later mounted on the M12 Gun Motor Carriage and saw action in 1944–45.

During the Second World War, some US-made guns were used for coast defense of US and Allied territories, such as Australia and Bermuda, typically on "Panama" mountings - circular concrete platforms with a raised centre section, with the carriage tires pivoting around the center section and the split trails spread out on rails at the edge of the platform.^[2]

This gun was designed by Colonel L. J. F. Filloux to fill a vital French Army requirement for a heavy artillery piece. The design proved a success and became the standard heavy field gun of the French from 1917 to the end of World War I.^[3] The weapon was pressed into service quickly, to remedy the shortage of such weapons in the French inventory. This weapon became the "Canon de 155 Grande Puissance Filloux mle 1917", named by French Army as the Canon de 155mm GPF (Model of 1917). The guns were produced by Atelier de Puteaux (APX), Renault and Atelier de Bourges (ABS).^[4]

During the First World War, the gun was eventually taken on by the American Expeditionary Force as a standard long-range artillery piece.^[5] At the beginning of the Second World War the French guns were still in service and more than 450 guns were operational in May–June 1940.^[6][7]

The GPF-CA was a variant of the GPF that used a longer chamber (chambre allongée or CA). It was produced by Puteaux from 1918 to enable the firing of heavier shells.^[4]

The US M1918 155 mm GPF was a copy of the French 1917 field gun and used by the US Army, Philippines and US Marines up to 1945.^[8] The United States Army paid for and subsequently copied, the Model 1918 (M1918) gun. During the Second World War the 155 mm guns were taken out of storage and used for coast defense on American shores and in Allied territories such as the Philippines and Australia. They were also used in the Philippines, Guadalcanal and North Africa campaign until more modern artillery was available. Ultimately, both the US Army and Marine Corps phased out their M1918 guns for the 155 mm M1A1 "Long Tom" beginning in 1942. The M1918 was also fitted to the M12 Gun Motor Carriage as a self-propelled gun (SPG) and used from 1943 to 1945.^{[citation needed]}

In 1939, Captain Touzard, French Army, proposed a new carriage for the GPF-T. It improved the mobility but also reduced the preparation time.^[4] The GPF-T was heavier (13.7 tonnes (13.5 long tons; 15.1 short tons)) but could be towed at a speed up to 36 kilometres per hour (22 mph). Around 60 guns were in service in May 1940.^[6]

Many of the guns fielded by the French in 1940 were captured and used by Germany for the rest of the war. In German service, the standard GPF version was known as the 15,5 cm K 418(f), the GPF-CA as the 15,5 cm K 417(f) and the GPF-T as the 15,5 cm K 419(f). It served with heavy artillery battalions in the Afrika Korps and on coast defense duties.^[4][9] On D-Day in 1944, the German Army had over 50 of the 155 mm French guns in sites on the northern French beaches. A battery of six of these guns near four empty emplacements for larger guns was the cause of the actions at Pointe du Hoc in June 1944.^[10][3]

Many of these weapons survive as memorials. The following list is not exhaustive:^[11]

* one gun in marks Mississippi ( # 367 ) 1918-A1 Dodge Brothers

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• 
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  At Fort de la Pompelle near Reims, France
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  At Battery Moltke, Jersey, Channel Islands
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  Canon de 155 Grande Puissance Filloux (GPF) on display at the North 12th Street (East) gate of the Illinois Veterans Home complex in Quincy, IL.

• De Bange 155 mm cannon
• List of field guns
• United States home front during World War I

• BL 6 inch gun Mk XIX British equivalent
• 15 cm Kanone 16 German equivalent

• van der Vat, Dan; Eisenhower, John S. D. D-Day: The Greatest Invasion—A People's History. Bloomsbury Publishing Plc, ISBN 1-58234-314-4.
• Gander, Terry and Chamberlain, Peter. Weapons of the Third Reich: An Encyclopedic Survey of All Small Arms, Artillery and Special Weapons of the German Land Forces 1939–1945. New York: Doubleday, 1979 ISBN 0-385-15090-3
• Touzin, Pierre; Vauvillier, François (2006). Les Matériels de l'Armée Française: Les canons de la victoire, 1914–1918. Tome 1: L'Artillerie de Campagne. Paris: Histoire et Collections. ISBN 2-35250-022-2.
• 155-Millimeter Gun Materiel, Model of 1918 (Filloux) Handbook of artillery: including mobile, anti-aircraft and trench matériel (1920) US Army Ordnance Dept, May 1920. Pages 229–245.

• Cutler, Frederick Morse. The 55th artillery (C.A.C.) in the American expeditionary forces, France, 1918 (1920)
• List and pictures of WW1 surviving 155 mm GPF guns
• Handbook of the 155 mm Filloux gun materiel
• FortWiki.com, lists all US and Canadian forts
• Complete list of US forts and batteries at the Coast Defense Study Group
• 588th Field Artillery Battalion (155) European Tour, 1944-1945