SCMITR was part of an experimental military shotgun ammunition created in the 1970s by AAI Corporation. It was a variation on flechette ammunition, but instead of containing a bundle of tiny needle-like steel darts, the cartridge contained a stack of razor-edged stamped sheet-metal arrow shapes designed to fly aerodynamically. It was considered to be very promising (in terms of lethality and effective range) but prohibitively expensive to manufacture, so it has never been mass-produced. [1] [2]
SCMITR was part of the CAWS (Close Assault Weapon System) program, which investigated ~20 mm smoothbore weapons (basically combat shotguns) designed to be effective to ranges of 150 metres against combatants wearing body armor. Flechettes, with their high sectional density, were ideal for penetrating rigid or soft composite armor, but the wounds caused by the tiny darts were considered insufficient to disable an enemy combatant, as the tiny hole would quickly clot and cause relatively little bleeding. The SCMITR darts had the same sectional density as flechettes, but the wide, flat shape of the SCMITR produced a larger, more disabling wound. Since the SCMITR darts were stamped from sheet metal, they had only two fins, which is not enough to provide stability. To overcome this, the fins were twisted slightly, which causes the dart to spin when flying, producing a stable projectile. [1]
The SCMITR cartridge was loaded with eight of these flechettes, each weighing about 1 gram. Dispersion was low, with all eight flechettes capable of hitting within a four-metre circle at a range of 150 metres. Retained velocity at 150 metres was 365 m/s, sufficient for the flechettes to penetrate 76 mm of pine or 3 mm of mild steel. [2]
The SCMITR project was cancelled with the cancellation of the CAWS project in the late 1980s. The most commonly encountered photograph, in Thomas Swearengen's book The World's Fighting Shotguns, shows a SCMITR shell clearly marked as a 20 gauge, smaller than the nominal 12 gauge bore used by the AAI CAWS entry.
A shotgun is a long-barreled firearm designed to shoot a straight-walled cartridge known as a shotshell, which discharges numerous small spherical projectiles called shot, or a single solid projectile called a slug. Shotguns are most commonly used as smoothbore firearms, meaning that their gun barrels have no rifling on the inner wall, but rifled barrels for shooting sabot slugs are also available.
Shrapnel shells were anti-personnel artillery munitions which carried many individual bullets close to a target area and then ejected them to allow them to continue along the shell's trajectory and strike targets individually. They relied almost entirely on the shell's velocity for their lethality. The munition has been obsolete since the end of World War I for anti-personnel use; high-explosive shells superseded it for that role. The functioning and principles behind shrapnel shells are fundamentally different from high-explosive shell fragmentation. Shrapnel is named after Lieutenant-General Henry Shrapnel, a Royal Artillery officer whose experiments, initially conducted on his own time and at his own expense, culminated in the design and development of a new type of artillery shell.
A flechette or flèchette is a pointed, fin-stabilized steel projectile. The name comes from French flèchette, meaning "little arrow" or "dart", and sometimes retains the grave accent in English: flèchette. They have been used as ballistic weapons since World War I. Delivery systems and methods of launching flechettes vary, from a single shot, to thousands in a single explosive round. The use of flechettes as antipersonnel weapons has been controversial.
The .50 BMG, also known as 12.7×99mm NATO, and designated as the 50 Browning by the C.I.P., is a .50 in (12.7 mm) caliber cartridge developed for the M2 Browning heavy machine gun in the late 1910s, entering official service in 1921. Under STANAG 4383, it is a standard service cartridge for NATO forces. The cartridge itself has been made in many variants: multiple generations of regular ball, tracer, armor-piercing (AP), incendiary, and saboted sub-caliber rounds. The rounds intended for machine guns are made into a continuous ammunition belt using metallic links.
A needlegun, also known as a needler, flechette gun or fletcher, is a firearm that fires small, sometimes fin-stabilized, metal darts or flechettes. Theoretically, the advantages of a needlegun over conventional projectile firearms are in its compact size, high rate of fire, and extreme muzzle velocity. The needle presents less frontal area than a bullet, producing less drag and thus more effective range than a wider projectile of the same mass and velocity. There have been experiments to make guided flechettes that can home in on targets.
A smoothbore weapon is one that has a barrel without rifling. Smoothbores range from handheld firearms to powerful tank guns and large artillery mortars.
The Steyr IWS 2000 is an Austrian single-shot bolt-action anti-materiel rifle produced by Steyr Mannlicher. IWS stands for Infantry Weapon System. Unlike other anti-tank rifle designs, it has a smoothbore barrel. This facilitates higher projectile velocities and allows a longer barrel service life, but the lack of gyroscopic spin-stabilization requires the projectile to have aerodynamic stabilizing fins instead. The IWS is chambered in a 15.2×169 mm armor-piercing fin-stabilized discarding-sabot cartridge, and is the first man-portable rifle to use this type of ammunition.
A combat shotgun is a shotgun issued by militaries for warfare. The earliest shotguns specifically designed for combat were the trench guns or trench shotguns issued in World War I. While limited in range, the multiple projectiles typically used in a shotgun shell provide increased hit probability unmatched by other small arms.
A shotgun cartridge, shotshell, or shell is a type of rimmed, cylindrical (straight-walled) ammunition used specifically in shotguns. It is typically loaded with numerous small, spherical sub-projectiles called shot. Shotguns typically use a smoothbore barrel with a tapered constriction at the muzzle to regulate the extent of scattering.
The Special Purpose Individual Weapon (SPIW) was a long-running United States Army program to develop, in part, a flechette-firing "rifle", though other concepts were also involved. The concepts continued to be tested under the Future Rifle Program and again in the 1980s under the Advanced Combat Rifle program, but neither program resulted in a system useful enough to warrant replacing the M16.
In current usage, a riot gun or less-lethal launcher is a type of firearm used to fire "non-lethal" or "less-lethal" ammunition for the purpose of suppressing riots or apprehending suspects with minimal harm or risk. Less-lethal launchers may be special purpose firearms designed for riot control use, or standard firearms, usually shotguns and grenade launchers, adapted for riot control use with appropriate ammunition. The ammunition is most commonly found in 12 gauge shotguns and 37mm or 40 mm grenade launchers.
The M67 recoilless rifle is a 90 mm anti-tank recoilless rifle made in the United States and later in South Korea. It could also be employed in an anti-personnel role with the use of the M590 antipersonnel round. It was designed to be fired primarily from the ground using the bipod and monopod, but could also be fired from the shoulder using the folded bipod as a shoulder rest and the monopod as a front grip. The weapon was air-cooled and breech-loaded, and fired fixed ammunition. It is a direct fire weapon employing stadia lines to allow simple range finding, based on a typical tank target bridging the lines once in range.
A shotgun slug is a heavy projectile made of lead, copper, or other material and fired from a shotgun. Slugs are designed for hunting large game, and other uses, particularly in areas near human population where their short range and slow speed helps increase safety margin. The first effective modern shotgun slug was introduced by Wilhelm Brenneke in 1898, and his design remains in use today. Most shotgun slugs are designed to be fired through a cylinder bore, improved cylinder choke, rifled choke tubes, or fully rifled bores. Slugs differ from round ball lead projectiles in that they are stabilized in some manner.
The Steyr ACR was a prototype flechette-firing assault rifle built for the US Army's Advanced Combat Rifle program of 1989/90. Although the Steyr design proved effective, as did most of the weapons submitted, the entire ACR program ended with none of the entrants achieving performance 100% better than the M16A2, the baseline for a successful ACR weapon.
The Advanced Combat Rifle (ACR) was a United States Army program, started in 1986, to find a replacement for the M16 assault rifle. Under the stress of battle the average soldier with an M16 may shoot a target at 45 meters, but hit probability is reduced to one out of ten shots on target by 220 meters. Because of this, the ACR program was initiated in the late 1980s to create a weapon that could double the hit probability. The ACR program was preceded by older programs such as the Special Purpose Individual Weapon. The program ended in 1990 after an expenditure of approximately US$300 million.
The Heckler & Koch HK CAWS is a prototype automatic shotgun—designed as a combat shotgun—co-produced by Heckler & Koch and Winchester/Olin during the 1980s. It was Heckler & Koch's entry into the U.S. military's Close Assault Weapon System program.
An underwater firearm is a firearm designed for use underwater. Underwater firearms or needleguns usually fire flechettes or spear-like bolts instead of standard bullets. These may be fired by pressurised gas.
Military use of combat shotguns through the 20th century has created a need for ammunition maximizing the combat effectiveness of such weapons within the limitations of international law. 12-gauge has been widely accepted as an appropriate bore diameter to provide an effective number of projectiles within an acceptable recoil. Early 12-gauge popularity for sporting purposes produced a large number of repeating firearms designs readily adaptable to military purposes.
The AAI CAWS 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.
The AAI ACR was a prototype flechette-firing assault rifle built for the US Army's Advanced Combat Rifle program of 1989/90. Although the AAI design proved effective, as did most of the weapons submitted, the entire ACR program ended with none of the entrants achieving performance 100% better than the M16A2, the baseline for a successful ACR weapon.