A poliorceticon ( Greek : πολιορκητικόν , also transliterated poliorketikon , poliorketika in the plural) is any member of the genre of Byzantine literature dealing with manuals on siege warfare , which is formally known as poliorcetics . As with much Byzantine literature, the poliorcetica tend to be compendia of earlier guides illustrated with Biblical and Classical anecdotes. The extent to which they might be up-to-date or representative of actual experiences in the field is sometimes questionable and greatly depends upon the author.
52-604: Composed as they were during the era immediately antecedent to the arrival of heavy artillery , the poliorcetica tend to focus less upon large machines and more upon techniques for bringing men close to fortifications, as well as on ways of undermining these once attacking forces are positioned. These Byzantine manuals also tend to give a good amount of insight on morale and advice on psychological defense employable by those being besieged, either to avoid betrayal or dissension harmful to successful and prolonged defense. They also cover means of avoiding one's own betrayal when invested by
104-503: A rifled barrel, the distance is measured between opposing lands or between opposing grooves ; groove measurements are common in cartridge designations originating in the United States , while land measurements are more common elsewhere in the world. Measurements "across the grooves" are used for maximum precision because rifling and the specific caliber so measured is the result of final machining process which cuts grooves into
156-692: A " 30 caliber rifle", which could accommodate any of a wide range of cartridges using a roughly 0.30 inches (7.6 mm) projectile; or as a "22 rimfire", referring to any rimfire firearms firing cartridges with a 22 caliber projectile. However, there can be significant differences in nominal bullet and bore dimensions, and all cartridges so "categorized" are not automatically identical in actual caliber. For example, 303 British firearms and projectiles are often "categorized" as ".30-caliber" alongside several dozen U.S. "30-caliber" cartridges despite using bullets of .310–.312-inch (7.87–7.92 mm) diameter while all U.S. "30-caliber" centerfire rifle cartridges use
208-405: A .250 inch land diameter and .257 inch groove diameter. The .308 Winchester is measured across the grooves and uses a .308-in diameter (7.82-mm) bullet; the military-specification version is known as 7.62 × 51 mm NATO , so called because the bore diameter measured between the lands is 7.62 mm, and the cartridge has a case 51 mm long. Converting a rifle to fire a different cartridge in
260-480: A 205 mm (8.1 in)/75 calibre weapon. However, with the war ending before the gun was ready, this weapon was soon scrapped. Development continued during the inter-war era, although at a more limited pace as aircraft were expected to take over in the long-range bombardment role. Nevertheless, the Germans built a handful of powerful Krupp K5s and the largest artillery pieces (by caliber) ever used in combat:
312-455: A US " 45 caliber " firearm has a barrel diameter of roughly 0.45 inches (11.43mm). Barrel diameters can also be expressed using metric dimensions. For example, a "9 mm pistol" has a barrel diameter of about 9 millimeters. Since metric and US customary units do not convert evenly at this scale, metric conversions of caliber measured in decimal inches are typically approximations of the precise specifications in non-metric units, and vice versa. In
364-465: A ball diameter of more than 50 cm (20 in). These superguns were either manufactured by forging together longitudinal iron bars, held in place by iron rings, or cast in bronze with techniques generally similar to bell-founding. Known examples include the Pumhart von Steyr , Dulle Griet and Mons Meg (all iron) as well as the cast-bronze Faule Mette , Faule Grete and Dardanelles Gun . At
416-515: A bore diameter of 211 mm (8.3 in) and a barrel length of 34 metres (112 ft). It was fired from concealed fixed positions in the forest of Coucy . The British attempted to develop weapons to counter the Paris Gun, but none was ready for testing until after the Armistice . A 16 in (410 mm) gun under development by Vickers for a class of never-built Russian battleships
468-412: A common, standard .308-inch (7.82 mm) bullet outside diameter. Using bullets larger than design specifications causes excessive pressures, while undersize bullets cause low pressures, insufficient muzzle velocities and fouling that will eventually lead to excessive pressures. Makers of early cartridge arms had to invent methods of naming cartridges since no established convention existed then. One of
520-597: A different definition may apply , caliber (or calibre ; sometimes abbreviated as " cal ") is the specified nominal internal diameter of the gun barrel bore – regardless of how or where the bore is measured and whether the finished bore matches that specification. It is measured in inches or in millimeters . In the United States it is expressed in hundredths of an inch; in the United Kingdom in thousandths; and elsewhere in millimeters. For example,
572-432: A distance of 26 mi (42 km). Smoothbore cannon and carronade bores are designated by the weight in imperial pounds of spherical solid iron shot of diameter to fit the bore. Standard sizes are 6, 12, 18, 24, 32, and 42 pounds, with some non-standard weights using the same scheme. See Carronade#Ordnance . From about the mid-17th until the mid-19th century, the measurement of the bore of large gunpowder weapons
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#1732783286086624-598: A multiple of the bore diameter. For example, a 4-inch gun of 50 calibers would have a barrel 4 in × 50 = 200 in long (written as 4" L/50 or 4"/50). A 16-inch gun of 50 calibers (16" L/50) has a barrel length of 50 × 16 = 800 inches (66 ft 8 in). Both 14-in and 16-in navy guns were common in World War II. The British Royal Navy insisted on 50-cal guns on ships as it would allow 1,900 to 2,700 lb (860 to 1,220 kg) shells to travel at an initial velocity of up to 1,800 mph (2,897 km/h) to
676-486: A pound; therefore, its barrel is smaller than the 12-gauge. This metric is used in Russia as "caliber number": e.g., "shotgun of the 12 caliber." The 16th caliber is known as "lordly" ( Russian : барский ). While shotgun bores can be expressed in calibers (the .410 bore shotgun is measured as .410 in (10.4 mm) in diameter, unlike with rifles the actual bore diameter of a smoothbore shotgun varies significantly down
728-582: A railway bridge in Belgium). All of the major powers involved employed such weapons in limited numbers, typically between 280 and 305 mm (11 to 12 inches) although some larger weapons were also used. The longest-ranged and longest-barreled of the heavy guns deployed in World War I was the Paris Gun , which was used to bombard Paris from a distance of over 130 kilometres (81 mi). The gun had
780-432: A related expression. The gauge of a shotgun refers to how many lead spheres, each with a diameter equal to that of the bore, that amounts to one pound (454 g (1.0 lb)) in weight. In the case of a 12-gauge (18.5 mm) shotgun, it would take 12 spheres the size of the shotgun's bore to equal a pound. A numerically larger gauge indicates a smaller barrel: a 20-gauge (15.6 mm) shotgun requires more spheres to equal
832-405: A siege. Two examples of the genre are: Although not technically poliorcetica , other Byzantine military texts such as Kekaumenos 's Strategikon and Nikephoros Ouranos 's Taktika often include sections or chapters dealing with siege operations. Sources which were composed by soldiers or generals themselves are naturally the most invaluable of these for reconstructing actual procedures in
884-418: A threshold of 100 mm (3.9 in). Several grammatical changes were made to that latter in 1992 and the threshold was lowered in 2003 to yield the current definition, as endorsed by UN General Assembly Resolution 58/54. Historically, large-calibre weapons have included bombards and siege guns . In the context of late medieval siege warfare the term superguns applies to stone-firing bombards with
936-495: Is based. The following table lists some of the commonly used calibers where both metric and US customary units are used as equivalents. Due to variations in naming conventions, and the whims of the cartridge manufacturers, bullet diameters can vary widely from the diameter implied by the name. For example, a difference of 0.045 in (1.15 mm) occurs between the smallest and largest of the several cartridges designated as ".38 caliber". Shotguns are classed according to gauge,
988-419: Is much variance in the use of the term "small-bore", which over the years has changed considerably, with anything under 0.577 inches (14.7 mm) considered "small-bore" prior to the mid-19th century. While modern firearms are generally referred to by the name of the cartridge the gun is chambered for, they are still categorized together based on bore diameter. For example, a firearm might be described as
1040-614: The Siege of Constantinople in 1453. The extant Dardanelles Gun, cast by the Ottoman gunfounder Ali several years later, is assumed to have followed closely the outline of Orban's guns. A similar super-sized bombard was employed by the Ottoman navy aboard a carrack of possibly Venetian design at the Battle of Zonchio in 1499. In India, a large forge-welded iron cannon was built during
1092-581: The 1880s he had built guns of over 40 feet (12 m) in length that could fire 1,800 pound (810 kg) shells and punch through an incredible 30 inches (76 cm) of iron at a range of 8 mi (13 km). The gun was exhibited at the Royal Mining Engineering Jubilee Exhibition held at Newcastle in 1887 for Queen Victoria 's golden jubilee. Prior to World War I , the German military was especially interested in
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#17327832860861144-476: The 800 mm (31.5 in.) Schwerer Gustav and Dora . The latter had been designed specifically to defeat the Maginot Line , firing a 7,000 kg (15,000 lb) shell to a range of 37 km (23 mi). Although their original role proved unnecessary, Gustav was used successfully to destroy Soviet heavy fortifications, most notably those at Sevastopol . Dora was readied for combat at Stalingrad , but
1196-795: The Earth. Gerald Bull was assassinated in March 1990, terminating development, and the parts were confiscated by British customs after the Gulf War . It has been suggested that the US Navy had developed a supergun (actually a prototype railgun , known as the Electro-Magnetic Laboratory Rail Gun ), capable of shooting shells at 5,600 mph (9,012 km/h) or Mach 7 (seven times the speed of sound). Caliber In guns , particularly firearms , but not artillery, where
1248-435: The beginning of the development of superguns was the desire to increase the effect of the projectiles. To this end, master gunners first simply used larger powder loads. These, however, exerted larger pressure on the existing cannon and could make it burst, causing the death of the irreplaceable gunner with his crew (and even kings ). In addition, it was observed that, due to their higher velocity, stone balls were shattered by
1300-422: The bore diameter and the length of the cartridge case; for example, the 6.5×55mm Swedish cartridge has a bore diameter of 6.5 mm and a case length of 55 mm. The means of measuring a rifled bore varies, and may refer to the diameter of the lands or the grooves of the rifling. For example, the 257 Roberts and 250 Savage both use a .257 inch projectile; both 250 Savage and 257 Roberts rifle bores have
1352-545: The bullet weight in grains was designated, such as 45-70-405. This scheme was far more popular and was carried over after the advent of early smokeless powder cartridges such as the 30-30 Winchester and 22 Long . Later developments used terms to indicate relative power, such as .44 Special and .44 Magnum . Variations on these methods persist today, with new cartridges such as the 204 Ruger and 17 HMR (Hornady Magnum Rimfire). Metric diameters for small arms refer to cartridge dimensions and are expressed with an "×" between
1404-688: The characteristics of a gun , howitzer , mortar , or rocket , capable of engaging surface targets by delivering primarily indirect fire , with a calibre of 76.2 mm (3.00 in) and above". This definition, shared by the Arms Trade Treaty and the Treaty on Conventional Armed Forces in Europe , is updated from an earlier definition in United Nations General Assembly Resolution 46/36L, which set
1456-455: The contemporary English ( avoirdupois ) pound massed of approximately 454 g (1.001 lb). Thus, a French 32-pounder at the Battle of Trafalgar threw a shot with 1.138 kg (2.51 lb) more mass than an English 32-pounder. Complicating matters further, muzzle-loaded weapons require a significant gap between the sides of the tube bore and the surface of the shot. This is necessary so
1508-597: The development of superweapons due to the need for the Schlieffen plan to march past a line of Belgian fortifications constructed specifically to stop such an invasion route. During the opening phases of the war, the Germans employed a 420 mm (17 in) Krupp howitzer (the Big Bertha ) and two 305 mm (12.0 in) Skoda Mörser M. 11 mortars to reduce the famous fortresses of Liège and Namur . Their low overland mobility made them arrive later than
1560-675: The development of the Grand Slam bomb . It was used from March 1943 through February 1945. Canadian engineer Gerald Bull became interested in the possibility of using 'superguns' in place of rockets to insert payloads into orbit. He lobbied for the start of Project HARP to investigate this concept in the 1960s, using paired ex-US Navy 16"/50 caliber Mark 7 gun barrels welded end-to-end. Three of these 16"/50 (406 mm) guns were emplaced, one in Quebec , Canada, another in Barbados , and
1612-544: The early established cartridge arms was the Spencer repeating rifle , which Union forces used in the American Civil War . It was named based on the chamber dimensions, rather than the bore diameter, with the earliest cartridge called the "No. 56 cartridge", indicating a chamber diameter of .56 in; the bore diameter varied considerably, from .52 to .54 in. Later various derivatives were created using
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1664-432: The end of their barrel life, whereby the rifling is worn down to a point where a rifle loses some of its accuracy , the choice to make a caliber or cartridge change is often done at the same time as when a new rifle barrel is fitted to the rifle by a gunsmith . There are a few important factors to consider when converting a rifle to a different caliber or cartridge. The action of the rifle should be long enough to contain
1716-504: The field. The English word poliorcetic (relating to the siege of cities) derives from Greek poliorkētikos , from poliorkētēs "taker of cities" (from poliorkein to besiege, from polis city + herkos fence, enclosure). Heavy artillery The formal definition of large-calibre artillery used by the United Nations Register of Conventional Arms (UNROCA) is " guns , howitzers , artillery pieces , combining
1768-588: The first breech-loading rifled artillery pieces, constructed a 600-pounder 'monster gun' of then extraordinary size at the Elswick Ordnance Company in Newcastle . The gun was a rifled muzzle-loader of 22,000 kg (49,000 lb) that fired shells of up to 600 pounds (270 kg) and could pierce 4.5 inches (11.4 cm) of iron armour. Armstrong identified them as "shunt" guns, but they were soon popularly known as "monster" guns. By
1820-663: The huge weapons were thwarted by massive Royal Air Force bombing raids, which made further attempts futile. Two smaller prototype versions of the gun were used during the Battle of the Bulge . During World War II, the British developed an experimental 13.5/8 inch hypervelocity gun named Bruce, which was deployed near St Margaret's in Kent among their cross-Channel guns . It was intended only for stratospheric experiments, primarily with smoke shells. These experiments were important in
1872-508: The impact on the walls rather than smashing them. Thus, the mass of the cannon balls and, consequently, of the ordnance too continually increased, finally culminating in giant cannon like the Pumhart von Steyr which fired a 690 kg (1,520 lb) ball. Apart from the anticipated improvement in penetrating power, other factors such as prestige and a potential deterrent effect also played an important role. For all their manufacturing quality
1924-586: The infantry at Liège, so several infantry assaults were made with heavy loss of life and generally little success. The guns arrived a few days later and reduced the forts at Liège one-by-one over a short period of a few days. Larger artillery after this opening period was generally limited to railway guns , which had much greater mobility, or naval monitors (two of the British Lord Clive class monitors were fitted with an 18-inch (457 mm) gun, and HMS General Wolfe fired 33 km (21 mi) at
1976-421: The length of the barrel, with the use of chokes and back-boring. In the United Kingdom, "gauge" is referred to as "bore" and in the United States "bore" is referred to as "gauge", e.g. a "12-bore shotgun or 12-gauge shotgun" has a bore or gauge that can accommodate a lead sphere weighing 1/12th of a pound. The term caliber is used as a measure of length of artillery barrels from muzzle to breech, expressed as
2028-455: The most common sizes encountered, although larger, smaller and intermediate sizes existed. In practice, though, significant variation occurred in the actual mass of the projectile for a given nominal shot weight. The country of manufacture is a significant consideration when determining bore diameters. For example, the French livre , until 1812, had a mass of 489.5 g (1.079 lb), whilst
2080-426: The new cartridge, the magazine should also be able to hold the new cartridge, the bolt face should be the correct diameter and the extractor the correct size to hold the head of the new cartridge. The most common of these caliber conversions on rifles, are usually done to change from a parent cartridge to a new cartridge based on it, like when converting a rifle to a 6.5 mm Creedmoor from a 308 Winchester on which it
2132-405: The projectile may be inserted from the mouth to the base of the tube and seated securely adjacent the propellant charge with relative ease. The gap, called windage , increases the size of the bore with respect to the diameter of the shot somewhere between 10% and 20% depending upon the year the tube was cast and the foundry responsible. The relationship between bore diameter and projectile weight
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2184-513: The reign of Raghunatha Nayak (1600–1645), and was then one of the largest cannons in the world. Artillery was used by Indian armies predominantly for defending against besieging armies. With the new metallurgical methods and precision engineering of the Industrial Revolution , a revolution in armaments, including artillery took place. In the 1860s, the industrialist Sir William Armstrong , who had already built one of
2236-402: The rough bore, leaving the "lands" behind. Good performance requires a concentric, straight bore that accurately centers the projectile within the barrel, in preference to a "tight" fit which can be achieved even with off-center, crooked bores that cause excessive friction, fouling and an out-of-balance, wobbling projectile in flight. Calibers fall into four general categories by size: There
2288-567: The same basic cartridge, but with smaller-diameter bullets; these were named by the cartridge diameter at the base and mouth. The original No. 56 became the .56-56, and the smaller versions, .56-52, .56-50, and .56-46. The 56–52, the most common of the new calibers, used a 50-cal bullet. Other black powder-era cartridges used naming schemes that appeared similar, but measured entirely different characteristics; 45-70 , 44-40 , and 32-20 were designated by bullet diameter to hundredths of an inch and standard black powder charge in grains . Optionally,
2340-504: The same bore diameter, often involves merely re-chambering the barrel to the new cartridge dimensions, if the rim diameter of the new cartridge matches that of the old cartridge. Converting a rifle to fire a different cartridge in a different caliber and bore as what it initially was, means that the barrel of the rifle will also need to be changed. Because many competitive precision rifle shooters often shoot thousands of rounds per year both for practice and competitions, and they more often reach
2392-525: The second half of the 15th century, further development in siege technology concentrated on the Hauptbüchse , and bombards largely disappeared from the leading artillery arsenal of the dukes of Burgundy . At about the same time super-sized bombards were phased out in Western Europe, the technology was transmitted to the Ottoman army by one Orban , a Hungarian gunfounder, on the occasion of
2444-468: The superguns were only moderately successful. Their military effectiveness turned out to be out of all proportion to their overwhelming logistical demands and financial costs. For the cost of a single supergun, two or three large bombards with a reasonably smaller caliber (in German Hauptbüchse ) could be produced whose firepower was enough to shatter any medieval wall, in particular when it
2496-464: The third near Yuma, Arizona . HARP was later cancelled, and Bull turned to military designs, eventually developing the GC-45 howitzer . Some years later, Bull interested Saddam Hussein in funding Project Babylon . The objective of this project is not certain, but one possibility is that it was intended to develop a gun capable of firing an object into orbit , whence it could then drop onto any place on
2548-523: Was concentrated in a battery . Due to their less bulky dimensions and higher rate of fire, these artillery pieces could be more flexibly deployed and caused more destruction in any given length of time. Furthermore, the transition from stone to smaller, but much more devastating iron balls meant that super-sized bores became unnecessary. The caliber of a 50 lb (23 kg) ball, for example, could be reduced from 28 to 18 cm (11.0 to 7.1 in) when using an iron projectile instead. Thus, as early as
2600-469: Was converted and lined down to 205 mm (8.1 in), with the designation "8-inch sub-calibre Mark I". The barrel was 120 calibres long. Testing commenced in February 1919, but after only six rounds were fired a crack was discovered, and the gun was scrapped in 1928. A weapon of similar concept, the "8-inch sub-calibre Mark II", was converted from a 12-inch gun (either Mark XI, XI*, or XII), producing
2652-444: Was usually expressed as the weight of its iron shot in pounds . Iron shot was used as the standard reference because iron was the most common material used for artillery ammunition during that period, and solid spherical shot the most common form encountered. Artillery was classified thereby into standard categories, with the 3-pounder, 4-pounder, 6-pounder, 8-pounder, 9-pounder, 12-pounder, 18-pounder, 24-pounder, and 32-pounder being
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#17327832860862704-505: Was withdrawn before it could be used. Development might have continued but for the ever-increasing Allied air power, which limited Hitler 's options in terms of re-opening bombing attacks on London . This led to the development of the V-3 "London Gun" or " Hochdruckpumpe ", fired from Mimoyecques in the Pas de Calais , about 95 miles (153 km) away. Two attempts to build underground bunkers for
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