During World War I it became the standard heavy howitzer of the French Army during the later stages of the war. 2043 were still in service with France in 1939. The Germans designated guns that fell into their hands as the 15.5 cm sFH 414(f).
Prior to 1917, the United States had used a 6-inch howitzer of a different design, but discarded it as unsatisfactory in favor of this French gun which the US found had withstood the tests of war and had proven in every way to be superior to all other howitzers of the same or similar caliber. The United States purchased 1,503 examples of the Mle 1917 from France and adopted it as the 155 mm Howitzer Carriage, Model of 1917 (Schneider), as the standard or regulation howitzer for the United States Army.
The United States also paid $560,000 for non-exclusive rights to the design and working drawings. In addition to the 1503 examples purchased in France and used there, 626 were manufactured by or for the US in the United States (stated to have been at a cost of more than $10,000,000). The Model 1918 built in the US differed somewhat from French models, with a straight rather than curved shield, rubber rather than steel tyres on wheels, a pivoting spade and a slightly different firing mechanism. US units were in action in France in 1918 with the 1,503 French-built guns. The first US regiment equipped with US-made guns was about to embark for France when World War I ended. The 1,503 as had been purchased from France were brought to the United States in 1919.
Both the M1917 and M1918 howitzers were upgraded with air brakes, new metal wheels and pneumatic tires during the interwar period and remained the standard American heavy howitzers until superseded by the M1 howitzer beginning in late 1942. They saw combat with both U.S. Army and Marine artillery units throughout World War II.
Some were sold to Russia during the war, but nothing is known of numbers or their use. Apparently the Soviets rebarreled surviving howitzers to use their standard 152 mm cased ammunition, but none seem to be on hand on 22 June 1941 at the start of Operation Barbarossa although the Germans captured some and gave them the designation of 15.5 cm sFH 449(r).
Schneider sold four C15S and eight C17S howitzers to Finland during the 1920s, known in Finland as the 152 H/15 and 152 H/17. These were rebarreled in Finland's standard 152 mm although they retained their original breeches, which meant that the H/15 used Russian-style cartridge cases and the H/17 used bagged powder. The H/15 had steel-rimmed wooden wheels that were suitable only for horse-traction, but these were later replaced by wheels with sponge rubber tires more suitable for motor traction. They were used for training during peacetime. During the Winter War the H/15s served with the 3rd Separate Heavy Artillery Battery while the H/17s were assigned to Heavy Artillery Battalion 3. During the Continuation War they saw combat with Heavy Artillery Battalions 24 and 25 as well as Field Artillery Regiment 3. They were retired after the end of World War II.
Germany sold a total of 166 captured howitzers to Finland, the first batch of 15 arriving in October 1940 and 147 arriving over the course of 1941. The last four arrived in 1944. They were heavily used during the Continuation War, serving with five heavy artillery battalions and eight field artillery battalions. Only 14 were lost to the Soviets in 1944. The remaining howitzers were used for live-fire training and warehoused for future use. New twin pneumatic wheels were fitted during the 1960s, and the guns were retained through the 1980s for live-fire training.
Poland acquired some C17S from France after the end of World War I and bought a license as well. They designated it as the Haubica 155mm wz. 1917. Some 340 were in service in September 1939 when the Germans invaded. Each of 39 Polish active infantry divisions had a horse-drawn heavy artillery battalion with three 155 mm howitzers and three 105 mm guns (they were absent in reserve divisions). There were also twelve heavy artillery battalions of C-in-C reserve, each with twelve howitzers. The rest were in reserve. Captured Polish howitzers were taken into German service as the 15.5 cm sFH 17(p).
Portugal acquired a batery of 4 pieces in the World War I integrated in the Portuguese Expeditionary Corps. They were retired in 1945.
The Argentine Army used two variants of this gun, locally called Obús Schneider L.15.05 modelo 1928calibre 155 mm and Obús Schneider L.30.05 modelo 1928 calibre 155 mm. Some of them were still used for training in the 1980s at the Colegio Militar de la Nación. Some were donated to neighnouring countries.
18 American guns were issued to the 2/1st Field Regiment, Royal Australian Artillery in the Middle East during December 1941. All were brought back to Australia when the regiment returned in 1942. Three guns are believed to be in various displays and memorials.
Belgium received some howitzers from France during World War I, but quantities are unknown. Weapons captured after Belgium's surrender in 1940 received the designation of 15.5 cm sFH 413(b) by the Germans.
The Bolivian Army received in 1976 a donation of 16 howitzers from the Argentine Army. Corresponding to both models used in Argentina and known as Obús Schneider L.15.05 modelo 1928calibre 155 mm and Obús Schneider L.30.05 modelo 1928 calibre 155 mm. The shipment Consisted of 2 batteries (each with 4 pieces) from each model. The guns are still in service in the artillery regiments ReA-2 "BOLÍVAR" (1st MECHANIZED BRIGADE) and RA-3 "PISAGUA" (3rd ARMY DIVISION).
Greece had a total of 96 howitzers when the Greco-Italian War began in October 1940. They were assigned to the corps-level heavy artillery battalions. Italy seized them after Greece surrendered in May 1941.
Thirty-six C17S's were in Yugoslav service by the 1920s although it is unclear whether these were weapons furnished to Serbia during World War I or bought by Yugoslavia during the 1920s.
Italy captured 8 during the Battle of France and 96 from Greece during the Balkan Campaign and placed them into service as the Obice da 155/14 PB. Howitzer seized by Germany after Italy's surrender in 1943 were placed into service as the 15.5 cm sFH 414(i).
Exactly how many howitzers were captured by Germany in the early years of World War II is not known, but Germany sold a number to Finland, reinforced the Atlantic Wall with 100 and equipped second-line infantry and static divisions based in France such as the 331st, 709th, 711th, and the 716th.
The first guns were procured in France in 1917, the weapon being declared standard for Army use in November 1922, although their first military use was in Africa in 1921 during the assault at Turiet Hamed. The gun was also built under license at Trubia and were used by the Regimientos de Artillería Pesados (Heavy Artillery Regiments). One was captured by revolutionaries in the Trubia factory during the Asturian miners' strike of 1934, although it was ineffective due to the lack of fuzing for their shells; the gun was damaged when a dynamite cartridge bundle used as substitute for fuzeless shells exploded inside. The gun was heavily used during the Spanish Civil War by both sides. During the SCW and World War II some guns were used as coastal defence weapons to try improve Spanish coastal defences as nothing more suitable was available. It remained in service until the 1950s when they were replaced by more modern equipment. There are many surviving pieces, of Spanish and French construction, in museums and as monuments around Spain.