While no longer a major component of today's infantry units, the infantry support gun was a battlefield staple since the advent of the cast barrel. The infantry support gun proved a major player in the fighting of World War 2 and, in 1932, the expanding German Army adopted the 7.5cm leichtes Infanteriegeschutz 18 (7.5cm le.IG 18) ("Light Infantry Gun") infantry support gun system. Design work on the type began in 1927 and manufacture was headed by the storied concern of Rheinmetall. Production spanned from 1932 into 1945, the last year of the war, with manufacture allowing for some 12,000 units to be delivered.
Weighing some 880lbs, the IG 18 was not a light artillery piece. It required a crew of five for general operation and relied on a mover vehicle for towing. It could be moved about by the crew when short distances were covered in battle - of course the terrain would play a major role. The weapon, as a complete, system, consisted of a short barrel and gun mount, a small angled shield for basic ballistics protection and a heavily-spoked solid wheel pairing. The mounting carriage was of a split trail type to which the legs opened and added recoil support when firing. The barrel measured three feet long and was 75mm in caliber.
The IG 18 fired a 75mm cased-cartridge type projectile weighing 13lbs with loading by the crew through a shotgun-style block breech mechanism. The gun mounting allowed for an elevation span of -10 to +73 degrees with traversal to either side of 12-degrees. An experiences, well-trained crew could reach a rate-of-fire of eight to twelve rounds per minute. Muzzle velocity was rated at 690 feet per second while maximum range was out to nearly 4,000 yards.
One notable variant of the IG 18 line was the 7.5cm le.GebIG 18 "mountain gun" which was the same artillery piece though designed to be broken down into six pieces for ease of travel. In this way, the weapon could be taken through the awkward mountain passes and fired from uneven ground. They proved valuable to lightly-armed forces such as German paratroopers as well.
The IG 18 series managed an active existence through all of World War 2 across countless campaigns where its short-/medium-ranged, relative light weight design and heavy hitting firepower were used alongside infantry maneuvers. The weapons could also be dug in and utilized in the defensive role.