The AAI CAWS ( Close Assault Weapon System ) is a prototype automatic shotgun —designed as a combat shotgun — produced by the AAI Corporation during the 1980s. It was AAI's entry into the U.S military's Close Assault Weapon System program.
49-504: It is a 12-round, 12-gauge shotgun with two firing modes: semi-auto and full-auto. In 1982, the United States was seeking entrants for their Close Assault Weapon System program. Grown out of previous combat shotgun programs, this program had inherited the specification from the RHINO program that had preceded it. These specifications required a magazine capacity of 10 rounds, a requirement for
98-496: 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
147-692: 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
196-405: 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
245-467: A 4-bore express rifle often used a 1,500-grain (3.43 oz; 97.20 g) bullet wrapped in paper to keep lead buildup to a minimum in the barrel. In either case, assuming a 4-ounce (110 g) mass for a 4-bore rifle bullet from this table would be inaccurate, although indicative. Caliber In guns , particularly firearms , but not artillery, where a different definition may apply , caliber (or calibre ; sometimes abbreviated as " cal ")
294-423: 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
343-426: A bore diameter (in inches) of approximately d n = 2 3 4 π 1 l b / n 0.4097 l b / i n 3 3 {\displaystyle d_{n}=2{\sqrt[{3}]{{\frac {3}{4\pi }}{\frac {1\mathrm {~lb} /n}{0.4097\mathrm {~lb/in^{3}} }}}}} Explanation: This simplifies to
392-412: 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
441-432: 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
490-592: 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
539-482: 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
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#1733093216586588-432: 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
637-545: A special cartridge larger than 12-ga and then provided a chamber adapter for the weapon to fire regular 12ga. The standard antipersonnel cartridge developed by AAI was loaded with eight 1 gram (0.035 oz) drag stabilized flechettes . All eight flechettes were able to hit a 4 m (4.4 yd) circle at 150 m (160 yd). The flechettes at that range had a velocity of 365 m/s (1,200 ft/s) and were capable of penetrating 76 mm (3.0 in) of pine or 3 mm (0.12 in) of mild steel. Although tested by
686-902: A specialist in rare and custom bores. The 14 gauge has not been loaded in the United States since the early 20th century, although the 2 + 9 ⁄ 16 -inch (65 mm) hull is still made in France. The very small 24 and 32 gauges are still produced and used in some European and South American countries. Punt guns , which use very large shells, are rarely encountered. Also seen in limited numbers are smoothbore firearms in calibers smaller than .360 such as .22 Long Rifle (UK No. 1 bore) and 9mm Flobert rimfire (UK No. 3 bore), designed for short-range pest control and garden guns . The No. 2 bore (7 mm) has long been obsolete. All three of these rimfires are available in shot and BB-cap. The 10 gauge narrowly escaped obsolescence when steel and other nontoxic shot became required for waterfowl hunting , since
735-495: 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,
784-428: Is commonly abbreviated as "ga.", "ga", or "G". An n -gauge diameter means that a ball of lead (density 11.34 g/cm or 0.4097 lb/in ) with that diameter has a mass equal to 1 / n part of the mass of the international avoirdupois pound (approx. 454 grams), that is, that n such lead balls could be cast from a pound weight of lead. Therefore, an n -gauge shotgun or n -bore rifle has
833-437: Is due to the larger swept volume of the overbored barrel. Once only found in expensive custom shotguns, overbored barrels are now becoming common in mass-marketed guns. Aftermarket backboring is also commonly done to reduce the weight of the barrel and move the center of mass backward for a better balance. Factory overbored barrels generally are made with a larger outside diameter, and will not have this reduction in weight—though
882-432: Is limited, as this table assumes the use of round ball, rather than conical bullets; for example, a typical 4-bore rifle from circa 1880 used a 2,000-grain (4.57 oz; 129.60 g) bullet, or sometimes slightly heavier, rather than using a 4-ounce (110 g) round lead ball. (Round balls lose velocity faster than conical bullets and have much steeper ballistic trajectories beyond about 75 yards or 69 metres) In contrast,
931-419: 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
980-616: Is related to the measurement of cannons , which were also measured by the weight of their iron round shot ; an eight-pounder would fire an 8 lb (3.6 kg) ball. Gauge is commonly used today in reference to shotguns , though historically it was also used in large double rifles , which were made in sizes up to 2 bore during their heyday in the 1880s, being originally loaded with black powder cartridges. These very large rifles, called " elephant guns ", were intended for use primarily in Africa and Asia for hunting large dangerous game. Gauge
1029-497: Is the 12 gauge, particularly in the United States. The 20-gauge shotgun is the next most popular size, being favored by shooters uncomfortable with the weight and recoil of a 12-gauge gun, and is popular for upland game hunting . The next most popular sizes are the .410 bore and the 28 gauge. The least popular sizes are the 10 gauge and the 16 gauge; while far less common than the other four gauges, they are still commercially available. Shotguns and shells exceeding 10 gauge, such as
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#17330932165861078-637: Is the bore size, right side is the case length The table below lists various gauge sizes with weights. The bores marked are found in punt guns, obsolete, or rare weapons only. However, 4 gauge was sometimes found used in blunderbuss guns made for coach defense and protection against piracy. The .410 and 23 mm are exceptions; they are actual bore sizes, not gauges. If the .410 bore and 23 mm diameters were measured using more traditional means, they would be equivalent to 67.62 gauge (.410 bore) and 6.278 gauge (23 mm), respectively. Note: Use of this table for estimating bullet masses for historical large-bore rifles
1127-464: 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, a US " 45 caliber " firearm has
1176-569: The U.S. military , the CAWS was canceled, and production, both military and civilian, has halted. This article relating to shotguns is a stub . You can help Misplaced Pages by expanding it . 12-gauge The gauge (in American English or more commonly referred to as bore in British English) of a firearm is a unit of measurement used to express the inner diameter (bore diameter) of
1225-432: The barrel . Gauge is determined from the weight of a solid sphere of lead that will fit the bore of the firearm and is expressed as the multiplicative inverse of the sphere's weight as a fraction of a pound, e.g., a one-twelfth pound lead ball fits a 12-gauge bore. Therefore with a 12-gauge, it would take 12 balls of lead of the same size as the 12 gauge shotgun's inner bore diameter to weigh 1 pound (454 grams). The term
1274-456: The 8 gauge, 6 gauge, 4 gauge, and 2 gauge are historically important in the United Kingdom and elsewhere in mainland Europe . Today, they are rarely manufactured. These shells are usually black powder paper or brass cartridges, as opposed to modern smokeless powder plastic or wax cartridges. The 18, 15, 11, 6, 3, and 2 gauge shells are the rarest of all; owners of these types of rare shotguns will usually have their ammunition custom loaded by
1323-422: 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
1372-420: The bore diameter of a shotgun is not a simple process, as it must be done away from either end. Shotgun bores are commonly "overbored" or "backbored", meaning that most of the bore (from the forcing cone to the choke) is slightly larger than the value given by the formula. This is claimed to reduce felt recoil and improve patterning. The recoil reduction is due to the larger bore producing a slower acceleration of
1421-545: 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
1470-451: 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
1519-531: 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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1568-432: 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
1617-408: The factory barrels will be tougher, since they have a normal barrel wall thickness. Firing slugs from overbored barrels can result in very inconsistent accuracy, as the slug may be incapable of obturating to fill the oversized bore. The six most common shotgun gauges, in descending order of size, are the 10 gauge, 12 gauge, 16 gauge, 20 gauge , 28 gauge, and .410 bore . By far the most popular
1666-422: The following formula for the internal diameter of the barrel of an n -gauge shotgun: d n = 1.67 / n 3 {\displaystyle d_{n}=1.67/{\sqrt[{3}]{n}}} in inches, or d n = 42.4 / n 3 {\displaystyle d_{n}=42.4/{\sqrt[{3}]{n}}} in millimeters. Likewise, given the diameter in inches,
1715-480: The gauge is n = 4.66 / d n 3 {\displaystyle n=4.66/d_{n}^{3}} The gauge of firearms is determined by: 1 pound/gauge = weight of lead sphere. Caliber of the bore is then measured. Since shotguns were not originally intended to fire solid projectiles, but rather a compressible mass of shot, the actual diameter of the bore can vary. The fact that most shotgun bores are not cylindrical also causes deviations from
1764-401: The ideal bore diameter. The chamber of the gun is larger, to accommodate the thickness of the shotshell walls, and a "forcing cone" in front of the chamber reduces the diameter down to the bore diameter. The forcing cone can be as short as a fraction of an inch, or as long as a few inches on some guns. At the muzzle end of the barrel, the choke can constrict the bore even further, so measuring
1813-629: The larger shell could hold the much larger sizes of low-density steel shot needed to reach the ranges necessary for waterfowl hunting. The move to steel shot reduced the use of 16 and 20 gauges for waterfowl hunting, and the shorter, 2 + 3 ⁄ 4 -inch (70 mm), 12-gauge shells as well. However, the 3 + 1 ⁄ 2 -inch (89 mm) 12-gauge shell, with its higher SAAMI pressure rating of 14,000 psi (97 MPa) compared to standard 2 + 3 ⁄ 4 -inch (70 mm) and 3-inch (76 mm) 12-gauge shells with their lower pressure rating of 11,500 psi (79 MPa), began to approach
1862-421: 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
1911-451: 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
1960-452: The new ammunition to be incompatible with commercial 12ga shotguns, that felt recoil be no greater than a Remington 870P firing M162 or M257 buckshot cartridges and that the system provide penetration and incapacitation capability significantly better than M162 and M257. In response to this, AAI developed their entrant, the AAI CAWS - a select fire , recoil operated, magazine fed shotgun. Using
2009-426: 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
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2058-469: The performance of the 3 + 1 ⁄ 2 -inch (89 mm) 10-gauge shells with a pressure rating of 11,000 psi (76 MPa). Newer nontoxic shots, such as bismuth or tungsten -nickel-iron alloys, and even tungsten- polymer blends, regain much or all of the performance loss, but are much more expensive than steel or lead shot. However, laboratory research indicates that tungsten alloys can actually be quite toxic internally. Legend: left side
2107-405: 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
2156-402: 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
2205-567: 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,
2254-504: 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
2303-419: The shot, and the patterning improvements are due to the larger muzzle diameter for the same choke constriction, which results in less shot deformation. A 12-gauge shotgun, nominally 18.5 mm (0.73 in), can range from a tight 18 mm (0.71 in) to an extreme overbore of 20 mm (0.79 in). Some also claim an increased velocity with the overbored barrels, up to 15 m/s (49 ft/s), which
2352-428: The standard M-16 stock and pistol grip, recoil operation and with an inline design, felt recoil was supposedly less than an M16. A shorter version, without stock, was also developed for Airborne forces . A day/night Reflex sight was offered as standard. To meet the requirements to both provide ammunition that could not be fired by commercial shotguns, but also for the weapon to fire commercial ammunition, AAI developed
2401-444: 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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