Howitzer

A howitzer is a type of artillery piece characterized by a relatively short barrel and the use of comparatively small propellant charges to propel projectiles over relatively high trajectories, with a steep angle of descent. In the taxonomies of artillery pieces used by European (and European-style) armies in the 17th to 20th Centuries, the howitzer stood between the "gun" (characterized by a longer barrel, larger propelling charges, smaller shells, higher velocities, and flatter trajectories) and the "mortar" (which was meant to fire at even higher angles of ascent and descent). Howitzers, like other artillery equipment, are usually organized in groups called batteries.

Brief history
In the early 20th century, the introduction of howitzers that were significantly larger than the heavy siege howitzers of the day made necessary the creation of a fourth category, that of "super-heavy siege howitzers". Weapons of this category include the famous Big Bertha of the German Army and the 15-inch (381 mm) howitzer of the British Royal Marine Artillery. These large howitzers were transported mechanically rather than by teams of horses. They were transported as several loads and had to be assembled at their firing position. These field howitzers introduced at the end of the 19th century could fire shells with high trajectories giving a steep angle of descent and, as a result, could strike targets that were protected by intervening obstacles. They could also fire shells that were about twice as large as shells fired by guns of the same size. Thus, while a 75 mm field gun that weighed one ton or so was limited to shells that weighed less than 8 kilograms, a 105 mm howitzer of the same weight could fire 15 kilogram shells. This is a matter of fundamental mechanics affecting the stability and hence the weight of the carriage. However, howitzers had a shorter maximum range than the equivalent gun.

As heavy field howitzers and light siege howitzers of the late 19th and early 20th centuries used ammunition of the same size and types, there was a marked tendency for the two types to merge. At first, this was largely a matter of the same basic weapon being employed on two different mountings. Later, as on-carriage recoil-absorbing systems eliminated many of the advantages that siege platforms had enjoyed over field carriages, the same combination of barrel assembly, recoil mechanism and carriage was used in both roles.

By the early 20th century, the differences between guns and howitzers were relative not absolute and generally recognized as follows:
 * Guns – higher velocity and longer range, single charge propellant, maximum elevation generally less than 35 degrees.
 * Howitzers – lower velocity and shorter range, multi-charge propellant, maximum elevation typically more than 45 degrees.

The onset of trench warfare after the first few months of the First World War greatly increased the demand for howitzers that gave a steep angle of descent, which were better suited than guns to the task of striking targets in a vertical plane (such as trenches), with large amounts of explosive and considerably less barrel wear. The German army was well equipped with howitzers, having far more at the beginning of the war than France.

Many howitzers introduced in the course of the First World War had longer barrels than pre-war howitzers. The standard German light field howitzer at the start of the war (the 10.5 cm leichte Feldhaubitze 98/09) had a barrel that was 16 calibers long, but the light field howitzer adopted by the German Army in 1916 (105 mm leichte Feldhaubitze 16, see on the left) had a barrel that was 22 calibers long. At the same time, new models of field gun introduced during that conflict, such as the 77 mm field gun adopted by the German Army in 1916 (7,7 cm Feldkanone 16) were often provided with carriages that allowed firing at comparatively high angles, and adjustable propellant cartridges. In other words, there was a marked tendency for howitzers to become more "gun-like", while guns were taking on some of the attributes of howitzers.

In the years after the First World War, the tendency of guns and howitzers to acquire each other's characteristics led to the renaissance of the concept of the gun-howitzer. This was a product of technical advances such as the French invention of autofrettage just before World War I, which led to stronger and lighter barrels, the use of cut-off gear to control recoil length depending on firing elevation angle, and the invention of muzzle brakes to reduce recoil forces. Like the gun-howitzers of the 19th century, those of the 20th century replaced both guns and howitzers.

Thus, the 25-pounder "gun-howitzer" of the British Army replaced both the 18-pounder field gun and the 4.5-inch howitzer. While this had the effect of simplifying such things as organization, training and the supply of ammunition, it created considerable confusion in the realm of nomenclature. In the US Army, however, the preferred term was "howitzer". Thus, as gun-howitzers replaced both guns and howitzers, words such as "obusier" (French) and "Haubitze" (German), which had originally been used to designate weapons with relatively short barrels, were applied to weapons with much longer barrels.

Types

 * A self-propelled howitzer is mounted on a tracked or wheeled motor vehicle. In many cases, it is protected by some sort of armor so that it superficially resembles a tank. This armor is designed primarily to protect the crew from shrapnel and small arms fire, not anti-armor weapons.
 * A pack howitzer is a relatively light howitzer that is designed to be easily broken down into several pieces, each of which is small enough to be carried by mule or pack-horse.
 * A mountain howitzer is a relatively light howitzer designed for use in mountainous terrain. Most, but not all, mountain howitzers are also pack howitzers.
 * A siege howitzer is a howitzer that is designed to be fired from a mounting on a fixed platform of some sort.
 * A field howitzer is a howitzer that is mobile enough to accompany a field army on campaign. It is, invariably, provided with a wheeled carriage of some sort.

References / notes

 * Information from Howitzer. Wikipedia: The free encyclopedia. Accessed 19 April, 2017.