Early Gunpowder Artillery
There is substantial evidence that the Arabs had developed the first gun by about 1300 in the form of a bamboo tube that could be charged with black powder and fired an arrow. It is also known that a device similar to a mortar that launched stone projectiles existed in China at about the same time. It is not known for certain which invention was first.
It is known that the Chinese developed rockets before this. A rocket is almost exactly like a cannon or mortar, but it works in the opposite way. Instead of firing a projectile, a rocket is turned upside down in relation to a cannon and the powder charge then propels the entire tube. There is no separate projectile used, but a rocket can be a formidable weapon by itself. Æ
A cannon that fired iron darts is known to have existed in the 1300s. The darts were wrapped with leather as a gasket to prevent windage, or the leaking of the propellant gas from around the projectile. The darts were somewhat like harpoons and were sometimes called garros. The gun was fitted to a trestle-type table and it had no provision for aiming or changing the elevation of the barrel. It also had no means of counteracting recoil, so it must not have been very powerful. It is also interesting to note that the bore on some very early guns did not appear to maintain a consistent diameter throughout their length. They were shaped more like clay vessels than cylinders.
Although explosively powered guns proliferated rapidly, mechanical artillery stayed in common use for several more centuries. This may have been partially due to the unreliability of early guns and powder. Until powder makers developed the corning process early in the 15th century, powder was extremely unpredictable. Mechanical siege engines were certainly still in use during the reign of King Henry VIII in England (1508-1547). It was not unusual to see both types of artillery in use by the same army in the same battle.
Early guns were naturally primitive and improvements came about steadily, but slowly. Although the concept of cannon might seem simple today, they are far more complex than is readily apparent. One aspect of gunnery that contributes to its imperceptible complexity is that guns are extremely high-precision machines. In fact, they are generally many times more precise in respect to machining tolerances than nearly any other types of manufactured items. At the time that the first explosively powered guns were invented, there were very few industrial capabilities and facilities in which to make them. Whole new industries and processes were born through cannon making. Æ
The guns made during this period were smooth-bore weapons. However, there was a period of brief experimentation with rifling in about 1500. The grooves were curiously straight. Rifling would not be tried again until about the 1800s. Æ
The Great Guns
As armament builders improved their craft during the fifteenth century and into the sixteenth, the race was on to develop larger and larger weapons. In fact, some of the weapons of this period were much larger caliber than any artillery since that time.
The largest recorded caliber gun ever made was the Great Mortar of Moscow known vicariously as the Tsar (Czar) Cannon built in 1586. It has a caliber of 36 inches or 914.4mm and is about 16.25 feet or 5 meters long. It reputedly weighs over 85,000 pounds (42.5 Yankee tons, 38000 kg). Tsar Fyodor I, son of Ivan IV, commissioned Andrei Chokhov to cast this great gun. It was designed to fire stone projectiles weighing about 2000 pounds or 900kg or some type of multiple shot such as grapeshot. The gun reputedly has never been fired and therefore still exists today at the Kremlin.
Another of the famous great guns is Mons Meg, currently located at Edinburgh Castle in Scotland. It is the surviving gun of a pair made for the Duke of Burgundy in 1457. Mons Meg was made as a siege gun and constructed of iron bars that were welded together at Mons, now in Belgium. The caliber of Mons Meg was 19.5 inches/0.5m and it fired stone projectiles that weighed upwards of 330 pounds/150kg. It is alleged that Meg could achieve a range of 1.5-2 miles/2.4–3.2km. However, some experts believe that it is unlikely that the gun had any accuracy beyond about 300 yards/274m. Because of the problems caused by its large size, the gun fell into disuse as a weapon; but Meg was kept for ceremonial use. The gun exploded in 1681 when it was fired as a birthday salute for the Duke of Albany. The ruined gun was dumped, but remembered fondly. Later, the gun was recovered and repaired as a museum piece, but it has never been fired since.
The very large guns of this period were limited in usefulness due to their enormous size. They used ammunition that was difficult to make and handle so they were primarily used for defending well-equipped fortresses. Any value they might have had in sieges was restricted to operations planned well in advance. The enormous guns were extremely heavy and their weight made them nearly immobile - not a good characteristic for a siege weapon. The Czar Cannon reputedly weighed over 40 tons/37000 Kg. Light by comparison, Mons Meg weighs over 6 tons/5500kg and legend has it that it could only be moved about 3 miles/4.8km a day at top speed. Nevertheless, the Scots used the gun against the English at the siege of Norham Castle in 1497.
The stone projectiles of the period were a great limitation because it required a skilled stone carver to form the stones into spheres that would fit the guns. Obviously projectiles made this way could be severely out of balance. Nevertheless, stone is plentiful in many areas and an army could avoid transporting ammunition in many cases by taking stone cutters along on a campaign.
Recoil was another factor that caused very large caliber guns to fall into disfavor. When a gun is fired, there is a force pushing it backwards. The heavier the projectile, the greater this backward force. This comes naturally from the basic physical principle that any action results in an equal and opposite reaction.
The real manifestation of this problem for early cannon builders was that the castings would eventually explode due to recoil, usually near the breech. The early solution to the problem was to mount cannon on wheels, whereby the recoil force dissipates by means of the cannon rolling backwards.
There is no way to eliminate recoil because it is just a manifestation of the laws of physics. Armament designers eventually found ways to redirect and dampen this force, but it is still there. In many cases, armament designers have been able to use some of the recoil to advantage. In modern guns, it can be used to clear the chamber for the next round.
Another technique that proved successful was to reinforce the barrel with iron bands. It was some time before metal technology brought the bronze cannon and it was around this period where strengthening the barrel by thickening it towards the breech began to appear. This technique helped considerably and bronze was much stronger than brass, but the very large guns were disappointing and they fell into disuse. Æ
Bronze Cannon Age
Successful bronze cannon were developed by the early 15th century. Some unverifiable records from Ghent (now in Belgium) credit Berthold Der Schwarze, a German Monk and Alchemist that is also known as Berthold Schwarz, as being the first European to cast bronze cannon. Bronze was not a new material at this time and its ability to be cast in large pieces was the property that made it attractive to cannon makers. The bronze used for making sculpture and bells that was available when gun makers began trying to make bronze cannon was not suitable for ordnance. New alloys that could withstand the shock and pressure that cannon must be able to handle had to be developed. This was more than simply a matter of finding the correct proportion of copper and tin. Not only was metallurgy a development problem, but also, foundry techniques had to be devised that kept the castings from having bubbles and sponginess. In the absence of science, all of these breakthroughs had to come through trial, error and intuition.
Early in the 1500s, cannon makers developed casting techniques that made good quality bronze cannon. Some of the innovations to foundry techniques consisted of using vitrified clay molds and casting the guns vertically in pits. Foundries discovered that casting guns breech down caused the metal to be more dense and stronger near the breech where the stresses are the highest. Cannon were cast with a core that could be removed thus leaving a hollow casting that could be bored to the desired diameter. Centering the core was difficult and locating fixtures called chaplets were used to hold the core in position. Chaplets were made of wrought iron and the bronze was cast over them. They remained part of the gun.
In the mid-1700s, machine shop methods advanced to the point that it was possible for advanced shops to cast solid blanks for guns and bore them out. This resulted in improvements of precision and improved the metal as well because the impurities tend to move toward the center of the casting.
The result of all of these developments was that successful bronze cannon were made and they quickly became the best artillery pieces up until about the 18th century in most places. The main exception was in England where cast-iron cannon were developed during the reign of King Henry VIII (16th century). The techniques for casting iron cannon were not developed outside of England until much later. While developing bronze casting techniques, cannon makers also incorporated another major technical innovation by adding trunnions to cannon. Trunnions are cylindrical projections on the side of the cannon barrel that serve as mounts for the gun and as the pivot for changing its elevation.
By the end of the 15th century, French armament manufacturers improved gun carriages and they were called limbers. They incorporated a frame to which the barrel was mounted that trailed to the ground and this was mounted on a pair of large wheels. The wheels and trailing end of the gun carriage absorbed recoil by rolling backwards and digging into the ground, respectively. As cannon became stronger, the trailing end would sometimes be dug into the earth. The gun always stayed on its mounting and wheels and this made cannon much more mobile. The trailing end of the gun carriage could be hitched to another limber that could be drawn by a team of horses.
In a similar development, British ordnance manufacturers developed four-wheeled carriages or trucks for naval guns by the mid-16th century. The purpose of the wheels was not so much to add mobility, but to counteract recoil. Gun carriages for naval guns could also be a big problem in stormy conditions because if cannon began to roll about they could batter and even sink a ship. To prevent this, naval cannon were secured by ropes. Nevertheless, they were the source of the saying “loose cannon,” used to denote a potentially serious or fatal problem.
In the period between the 15th and 19th centuries, one of the major advancements was simply the classification of cannon. Guns were separated into different classes according to the weight of the projectiles that they used, and all cannon of a specified size could use the same ammunition. Before this, each gun had to have its own special ammunition. This was really a significant and novel idea and probably the beginning of standardization and interchangeability, at least in the Renaissance.
During the eighteenth century, the Englishman Benjamin Robins made important scientific discoveries about artillery, and especially projectiles, but many of his discoveries were left unused for at least a hundred years. Gunnery methods of this era stayed nearly the same until about the mid-1800s. There were several substantial advances such as the cast iron cannon and then the cast steel cannon by about 1847, but in many cases, these developments were viewed as a joke by the military leaders of the day. In fact, the first cast steel cannon by Alfred Krupp, the innovation that it was, could not be sold and eventually was given away. However, Alfred Krupp eventually managed to sell steel cannon in great numbers.
It should be noted that the cannon of this period were about as dangerous to fire as they were to an opposing army. Many of the advancements by trial and error resulted in guns that were too dangerous to use. This was the case with an innovation by Gustavus II Adolphus of Sweden who introduced a leather gun 1626. The gun used a leather-wrapped copper tube for an almost composite construction and the total weight of the gun was reduced to about 90 pounds. The gun had a serious problem with overheating which caused it to be so dangerous that it was abandoned in 1631 for heavier, but safer, guns.
This was not the only problem with dangerous cannon. Cannon continued to be extremely dangerous to operate at least until cast steel models became commonplace. The most common problem was that the cannon tube would occasionally explode near the breech when firing. Several prominent people lost their lives when cannon exploded. In addition to the thousands of troops lost to exploding cannon, an exploding cannon killed King James II of Scotland at Kelso in 1460. In more recent times, an exploding cannon killed US Secretary of State Abel Upshur aboard the ship Princeton in mid-March 1844. Æ
Naval guns were equipped with a means of securing them to limit their rolling about. This was frequently in the form of an eye that a rope could be passed through. Gun carriages for naval guns could be a big problem in stormy conditions because if guns began to roll about they could batter and sink a ship. To prevent this, naval guns were secured by ropes. The ropes could then be connected to a counterweight and through the use of a block-and-tackle, recoil could be dissipated. By the time that navies began to build great battleships, guns were usually attached directly to ships. This became possible as gun makers found better ways to deal with recoil in the actual gun itself and ships began to be constructed of metal.
Not long after the introduction of guns, the potential for their adaptation to sea warfare was appreciated. In about 1509, the Venetian Navy equipped a fleet with guns mounted in the galleys of their ships. The oar-powered ships were deployed up the Po River to Ferrara (in present day Italy), where one of the first naval battles using guns ensued.
The guns aboard the Venetian ships were no match for the land-based artillery of the Duke of Ferrara, however, and the Venetian fleet was destroyed. This greatly increased the importance of artillery, but it also gave birth to an erroneous principle that lasted for another 400 years, the principle that naval guns were nearly always at a disadvantage to land-based artillery. This principle greatly affected the strategic and tactical use of naval guns until just before the birth of the great battleships in the 19th century. Some of the results of this were that navies concentrated on weapons for battle between ships and the use of naval forces for attacking land targets and supporting land operations was limited.
In the 1500s, a series of naval battles in the English Channel served to further define the tactical application of naval guns during this period. The British fleet engaged the Spanish Armada in the summer of 1588. The British relied on light guns (7.5 pound shot) with relatively long range in light and maneuverable ships while the Spaniards were equipped with heavy guns (about 17 pound shot) of short range in large, but less agile ships. The British tactics proved to be successful and they were able to inflict severe damage on the Spanish Armada while mostly staying out of range of the Spanish heavy guns. Furthermore, the Spanish guns quickly ran out of ammunition.
These experiences set the course for the application of naval guns up until the development of the great battleship in the late-19th century. In short, naval guns were generally of modest weight with relatively long range. Æ