The Field Gun is generally considered to be the smallest of standard artillery pieces, designed specifically for manoeuvrability and support of infantry. The carriage itself (particularly during the Napoleonic Wars) was given larger wheels than would otherwise be mounted onto the carriage, improving the turning circle and speed of the Field Gun around the field.
The Field Gun has evolved to use a variety of caliber and ammunition types. From the original iron cannon balls to the emergence of shells the Field Gun has evolved to fire virtually any type of ammunition at infantry within a reasonable range. A Field Gun is often referred to, wrongly, as a Howitzer the difference being that the Howitzer is capable of being aimed at any angle, while the Field Gun was normally limited to the range of adjustment on it's carriage.
The Field Gun is part of the larger group of firearms name Field Artillery. Their use was primarily focused upon quick engagement at random points on the field, disrupting the enemy forces movements and organisation before moving to a different point.
Napoleonic WarsEditThe Napoleonic Wars were dominated by Napoleon Bonaparte's use of his artillery units, particularly his deployment of Field guns. Although his most famous tactic of the "Grand Battery" (whereby a mass of cannon would join up in a single spot and bombard a single point) involved the Field Gun, Napoleon's most effective tactic would be to allow small groups of Field Guns to be towed around the field, before being unlimbered and unleashing a short barrage of shots. The Field Guns would then be limbered up again and towed to a new location.
First World WarEdit
The whole concept of Field Artillery evolved during the years between the Napoleonic Wars and the First World War. Virtually all artillery pieces could be mounted on rail or road to be moved, although focus remained on smaller artillery pieces, such as the Field Gun, that could be moved quickly in the field of battle.
Second World WarEdit
By the time of the Second World War the term Field Gun was being used to refer to any cannon or artillery piece that would fire at a low angle, while the term Howitzer would be designated to artillery pieces that could be angle higher. By this time the Field Gun, in its conventional role, had been combined to form self-propelling guns and anti-tank weapons.
The Field Gun has now become redundant as a firearm, replaced by the tank (for manouevrability) and by mortars capable of being deployed by infantry. Likewise even the largest artillery pieces, even those that would dwarf a Field Gun in power and size, can easily be moved around and are far more effective than the Field Gun, although some forces still refer to their artillery pieces as Field Guns.
Napoleon Total War (Video game) - Research materials provided in game