SCIMTR
Encyclopedia
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.
(Close Assault Weapon System) program, which investigated ~20 mm smoothbore
weapons (basically combat shotgun
s) 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 2 fin
s, which is not enough to provide stability. To overcome this, the fins are twisted slightly, which causes the dart to spin when flying, producing a stable projectile.
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.
, smaller than the nominal 12 gauge bore used by the AAI CAWS entry. The Joint Combat Shotgun program, which resulted in the adoption of the M1014 semi-automatic combat shotgun, is a more traditional design, a commercial shotgun adapted to military use, and uses conventional ammunition, including buckshot, shotgun slug
and less lethal ammunition. There is also mention of handgun
ammunition firing a single SCMITR projectile, for use by sky marshal
s.
Military
A military is an organization authorized by its greater society to use lethal force, usually including use of weapons, in defending its country by combating actual or perceived threats. The military may have additional functions of use to its greater society, such as advancing a political agenda e.g...
shotgun
Shotgun
A shotgun is a firearm that is usually designed to be fired from the shoulder, which uses the energy of a fixed shell to fire a number of small spherical pellets called shot, or a solid projectile called a slug...
ammunition
Ammunition
Ammunition is a generic term derived from the French language la munition which embraced all material used for war , but which in time came to refer specifically to gunpowder and artillery. The collective term for all types of ammunition is munitions...
created in the 1970s by AAI Corporation
AAI Corporation
AAI Corporation is an aerospace and defense development and manufacturing firm in Hunt Valley, Maryland, USA. It is formerly a wholly owned subsidiary of United Industrial Corporation, AAI was acquired by Textron in 2007 and currently is an operating unit of Textron Systems Corporation...
. It was a variation on flechette
Flechette
A flechette is a pointed steel projectile, with a vaned tail for stable flight. The name comes from French , "little arrow" or "dart", and sometimes retains the acute accent in English: fléchette.-Bulk and artillery use:...
ammunition, but instead of containing a bundle of tiny needle-like steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
darts
Dart (missile)
Darts are missile weapons, designed to fly such that a sharp, often weighted point will strike first. They can be distinguished from javelins by fletching and a shaft that is shorter and/or more flexible, and from arrows by the fact that they are not of the right length to use with a normal...
, the cartridge contained a stack of razor
Razor
A razor is a bladed tool primarily used in the removal of unwanted body hair through the act of shaving. Kinds of razors include straight razors, disposable razors and electric razors....
-edged stamped sheet-metal arrow
Arrow
An arrow is a shafted projectile that is shot with a bow. It predates recorded history and is common to most cultures.An arrow usually consists of a shaft with an arrowhead attached to the front end, with fletchings and a nock at the other.- History:...
shapes designed to fly aerodynamically. It was considered to be very promising (in terms of lethality
Lethality
Lethality is a term designating the ability of a weapon to kill. Most often this term is used when referring to chemical weapons, biological weapons, or their chemical components. The use of this term denotes the ability of these weapons to kill, but also the possibility that they may not kill...
and effective range) but prohibitively expensive to manufacture, so it has never been mass-produced.
Development
SCMITR was part of the CAWSSpecial Purpose Individual Weapon
The Special Purpose Individual Weapon was a long-running United States Army program to develop, in part, a workable flechette-based "rifle", though other concepts were also involved...
(Close Assault Weapon System) program, which investigated ~20 mm smoothbore
Smoothbore
A smoothbore weapon is one which has a barrel without rifling. Smoothbores range from handheld firearms to powerful tank guns and large artillery mortars.-History of firearms and rifling:...
weapons (basically combat shotgun
Combat shotgun
A combat shotgun is a shotgun that is intended for use in an offensive role, typically by a military force. The earliest shotguns specifically designed for combat were the trench guns or trench shotguns issued in World War I...
s) designed to be effective to ranges of 150 metres against combatants wearing body armor. Flechettes, with their high sectional density
Density
The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...
, 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 2 fin
Fin
A fin is a surface used for stability and/or to produce lift and thrust or to steer while traveling in water, air, or other fluid media, . The first use of the word was for the limbs of fish, but has been extended to include other animal limbs and man-made devices...
s, which is not enough to provide stability. To overcome this, the fins are twisted slightly, which causes the dart to spin when flying, producing a stable projectile.
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.
Applications
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 gaugeGauge (bore diameter)
The gauge of a firearm is a unit of measurement used to express the diameter of 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 . Thus...
, smaller than the nominal 12 gauge bore used by the AAI CAWS entry. The Joint Combat Shotgun program, which resulted in the adoption of the M1014 semi-automatic combat shotgun, is a more traditional design, a commercial shotgun adapted to military use, and uses conventional ammunition, including buckshot, shotgun slug
Shotgun slug
A shotgun slug is a heavy lead projectile, that may have pre-cut rifling, intended for use in a shotgun and often used for hunting large game. The first effective shotgun slug was introduced by Wilhelm Brenneke in 1898, and his design remains in use today...
and less lethal ammunition. There is also mention of handgun
Handgun
A handgun is a firearm designed to be held and operated by one hand. This characteristic differentiates handguns as a general class of firearms from long guns such as rifles and shotguns ....
ammunition firing a single SCMITR projectile, for use by sky marshal
Sky marshal
A sky marshal is an undercover law enforcement or counter terrorist agent on board a commercial aircraft to counter aircraft hijackings...
s.