Infantry support gun

Infantry support guns or Battalion guns are artillery weapons designed and used to increase firepower of infantry units they are intrinsic to; offering immediate tactical response to the needs of the unit's commanding officer. The designs are typically with short low velocity barrels, and light construction carriages allowing them to be more easily manoeuvred on the battlefield.

Development history
Infantry support guns were the first type of artillery employed by armed forces, initially in China, and later brought to Europe by the Mongol invasion. In their initial form, they lacked carriages or wheels, and were simple cast barrels called pots de fer in French, or vasi in Italian. These weapons were relatively small, immobile, and fired large bolts or quarrels. Along with increases in the sizes of ordnance (the barrels) came the requirement of easier transportation. This led to two divergent approaches, the very light hand-gun, and eventually the arquebus, while another avenue of development led to the light ordnance, now on wheeled carriages, such as the 2-pounder Culvern moyane, the 1-pounder Falcon, and the 3/4-pounder Falconet. These lighter Renaissance pieces eventually led to the development of the 3-pounder and 4-pounder regimental guns of the 17th century as well as the leather cannon, notably in the army of Gustavus Adolphus. The light field guns of the 17th century, commonly known as a drake in England, came in almost 100 different calibres, with each having its own distinct name, some of which were:
 * 5 pound, 3½ inch saker, weighing 1 ton
 * 4 pound, 3 inch minion, weighing 3/4 ton
 * 2 pound, 2¾ inch falcon, weighing 1/4 ton
 * 1 pound, 2 inch falconet, weighing 200lbs
 * ¾ pound, ¼ inch robinet, weighing 100lbs

The saker and falcon had point-blank ranges of 360 and 320 yards, and 2,170 and 1,920 yards extreme ranges respectively.

Although oxen were used to haul the heavier field and siege ordnance, some on wagons rather than limbers, they were too slow to keep up with the infantry, and so horses were used to pull the lighter pieces, leading to the development of the artillery carriage and horse team that survived until the late 19th century.

17th-19th century development
The first School of Artillery in Venice was opened early in the 16th century, and by the late 17th century the different old names of the lighter ordnance were abandoned, and replaced with the French canon, or cannon.

The first regimental guns in English service were ordered by King James II in 1686; two 3-pounders for each of the seven regiments (of one battalion each) encamped in Hyde Park. Attachment of guns to the infantry had practical reasons also. While the allocation of horses was reckoned at one for each 350-500 pounds of ordnance and its carriage, this was only true for availability of good horses and good roads, both in short supply due to unscrupulous civilian contractors and lack of road building technology. In cases where the work was excessive for horses alone, infantry would join them in pulling the guns, calculated at 80 lbs per infantryman, a load which remains at the upper limit of the average light infantry unit requirement today.

The 3 pounder Grasshopper cannon was in use with British forces in the 18th Century. Each British infantry battalion had an officer and 34 non commissioned officers and other ranks trained by the Royal Artillery to handle the two 3 or light 6 pounder guns battalion guns.

Frederick the Great of Prussia was the first to introduce artillery tactics for the regimental guns which were to accompany the infantry units as part of his reform of the Prussian artillery as a whole before and during the Seven Years War. This included the determination that canister shot was only effective at a range of 100 yards, same as that of the musket range, and therefore put the gunners into the environment of direct infantry combat due to Frederick's insistence that artillery should participate in the infantry attack.

The French artillery ordnance (barrels) was standardised into five calibres in the second half of the 17th century: 4-pounders (regimental guns), 8-pounders and 12-pounders (field artillery), 24-pounders and 32-pounders (garrison or fortress artillery).

Manufacture of the ordnance was also revolutionised by the early-18th century invention of the boring mechanism by the Swiss gun-founder Moritz of Geneva which allowed for a far greater precision achieved in the casting, in essence creating a huge lathe on which the barrel casting turned instead of the boring tool. Manufacture of cannonballs was also improved so the projectiles were now well-fitted to the bore of the ordnance, and after conducting experiments with gunpowder, the powder charges were determined to be one-third the weight of the shot (cannonball).

Frederick's artillery doctrine influenced the development of the French artillery troops, and after 1764 Jean Baptiste Vaquette de Gribeauval, the first Inspector of Artillery, after conducting trials in Strasbourg, reorganised French artillery units to provide them with greater mobility, changing length of the barrels to standard 18-calibre length, including the regimental 4-pounders. These were now pulled by four horses and used large six-wheeled vehicles that also included the caissons. The system of ordnance, carriages, ball, and powder charges introduced by de Gribeauval remained virtually unaltered through the French Revolutionary Wars and Napoleonic Wars.

Belgium

 * Canon de 76 FRC

The Canon de 76 FRC was a Belgian infantry support gun, produced by the Fonderie Royale des Canons (FRC). The gun was typically of 76 mm calibre; however, an optional 47 mm barrel could be fitted instead. The gun was designed for transport via a trailer towed by a vehicle. In 1940, the Wehrmacht redesignated these as 7.6 cm IG 260(b).

France

 * Canon d'Infantrie de 37 modele 1916 TRP

The Canon d'Infantrie de 37 modele 1916 TRP (37mm mle.1916) was a French infantry support gun, first used during World War I. The gun was used by a number of forces during and after the war. The US acquired a number of these guns, which they designated 37mm M1916; however, by 1941 the US Army had put these into storage (or scrapped them). Poland fielded a number. In 1940, the Wehrmacht began using these as 3.7 cm IG 152(f). During the First World War, the Japanese Type 11 was based on this design.

Germany

 * 7.5cm Infanteriegeschütz "L/13"
 * 7.5cm leichtes Infanteriegeschütz 18
 * 7.5cm Infanteriegeschütz 37
 * 15cm schweres Infanteriegeschütz 33
 * 7.6cm IG 260(b)

Japan

 * Type 11 (heavily inspired by France's Canon d'Infantrie de 37 modele 1916 TRP)


 * Type 92 Battalion Gun

Imperial Russia

 * 37 mm trench gun M1915

Italy

 * Cannone da 47/32 M35
 * Cannone da 65/17 modello 13
 * Cannone da 70/15

Soviet Union

 * 76.2-mm regimental gun M1927
 * 37 mm anti-tank gun M1930 (1-K)
 * 76.2-mm regimental gun M1943

United Kingdom

 * 1.59 inch Breech-Loading Vickers Q.F. Gun, Mk II ("Vickers-Crayford rocket gun")

United States

 * 37 mm Gun M3
 * M116 howitzer
 * 105 mm Howitzer M3

Modern times
Very few support guns are still in service with infantry units; their roles largely replaced in part by-
 * grenade launchers
 * light anti-tank weapons
 * heavier wire-guided missiles in engaging point targets such as structures.
 * Pack guns are similar in concept, but specifically refer to those guns that are meant to be disassembled into parts for movement, and are synonymous with mountain guns as infantry support weapons designed for use during mountain combat.
 * Airborne guns are those designed for use by paratroopers, and generally reflect similar design features of portability and lighter weight when compared to field artillery.
 * Mortars