Flechette


 * For the film producer, see Flechette (company).

The French word flechette means "little arrow" or dart projectile of steel that is sharp and pointed with a vaned tail for stable flight.

Bulk use
Flechettes were first used as an air-dropped weapon in World War I by combatants on both sides. These were about four inches long (10 cm) and weighed a couple of ounces (60 g). Dropped from aeroplanes or Zeppelins over enemy trenches or airfields, these gravity missiles were capable of penetrating a helmet and the wearer's skull. Similar weapons were 'Lazy Dogs' (or 'Devil Dogs'), used by the U.S. in the Korean and Vietnam Wars. These 1 3/4" length (4.5 cm) bomblets were air-dropped at height in canisters by aircraft or scattered from buckets by helicopter crews, reaching high sub-sonic speeds as they fell. Targeted at enemy personnel and unarmored vehicles, the flechette hit the targets with the force of a bullet.

Smaller flechettes were used in special artillery shells called "beehive" rounds (so named for the very distinctive whistling buzz made by thousands of flechettes flying downrange at supersonic speeds) and intended for use against troops in the open - a ballistic shell packed with flechettes was fired and set off by pressure-sensitive detonators, scattering flechettes and shrapnel in all directions. They were used in the Vietnam War by artillery gunners to defend their positions against infantry attacks.

Controversy
The use of artillery flechette rounds in populated areas has recently been criticized due to their use by the Israel Defense Forces in the Gaza Strip. These criticisms focus on the wide area of effect of artillery flechette rounds, and their use in areas with large civilian populations. Detractors argue that the such use of the rounds conflicts with the Fourth Geneva Convention provisions protecting non-combatants.

Heavy flechettes
Known by most forces as discarding sabot rounds, these anti-tank rounds can be more effective than high explosive devices; see kinetic energy penetrators. For reasons why a smaller diameter projectile is desirable, see external ballistics and terminal ballistics.

The M1A1 (United States Army Main Battle Tank) and the Challenger 2 (British Army MBT) both employ APFSDS (Armor-Piercing, Fin-Stabilized, Discarding Sabot) rounds as their primary AT capacity, fired from a 120-mm main gun.

The CBU-107 Passive Attack Weapon is an air-dropped guided bomb containing 3,700 non-explosive steel and tungsten penetrator rods of various sizes. It was designed to attack targets where an explosive effect may be undesirable, such as fuel storage tanks in civilian areas.

Controversy
Modern anti-tank penetrator rounds are most effective when made with the highest density materials practical, and a common choice is not tungsten, but depleted uranium, or DU, is in use by NATO forces. The controversy involves the residue of the use of DU rounds. Uranium metal is chemically very reactive, and the force of impact causes the round to ignite and burn. The resulting ash is a mixture of various uranium oxides, all of which are either known or suspected toxins. The depleted uranium in the round is radioactive, though less so than naturally occurring uranium ores.

Small arms ammunition
In the 1960s the United States Army began early developmental work on a flechette rifle cartridge. It fired steel darts that looked very much like steel nails with fins stamped into the back ("nails with tails"). The flechettes were 3 – 5 cm long, and 1 – 2 mm in diameter, with a 4 – 5 mm fin diameter. It was never fielded. Attempts have been made to develop a selective-fire flechette several times since, with mixed results. There were also experimental flechette rounds for the M203 grenade launcher and the 12-gauge shotgun, but the military eventually decided that standard ammunition worked best in both.

Flechette rounds were developed for small arms for a number of reasons. Being very small and light compared to traditional jacketed lead or steel bullets, flechette ammunition weighs less per round, and thus an infantryman can carry more. Second is the issue of recoil &mdash; for the same amount of kinetic energy, a lighter bullet (with a higher muzzle velocity) produces less recoil, and thus less shot dispersion in automatic fire. The last reason was the emergence of lightweight, flexible body armor for the average infantryman. A very high velocity, small diameter projectile is able to easily penetrate body armor. Also its mass-to-piercing-area ratio was much better than that of regular bullets.

However, the flechette has a number of weaknesses that limit its effectiveness as small arms ammunition. They tended to penetrate heavy armor less deeply than heavier, higher momentum rifle bullets. Their extreme light weight caused them to be deflected extremely easily; a single leaf, or even a raindrop, could destabilize a flechette and cause it to tumble wildly. Because of the hard nature of the flechette, it does not deform on impact, and while it penetrates extremely well, it produces very little tissue damage. The last issue with small arms flechettes is accuracy. To fire the finned flechette out of a smoothbore requires the use of a sabot. Since flechettes do not achieve sufficient stability when spun by rifling alone, the main source of stabilization is the fins. When the sabot separates, it can disturb the effectively unstabilized flechette, and cause deviations in its flight. Experiments to reduce problems associated with sabot separation have been performed, such as placing the sabot on the forward portion of the flechette, rather than the rear, and by fitting a sabot stripper in the muzzle to remove it with less disturbance to flight.

An interesting variation of the flechette that addresses its difficulties is the SCIMTR, developed as part of the CAWS project. Also, in 1989 and 1990 the U.S. Army experimented with the Steyr ACR. However, the rifle did not achieve the necessary performance to be considered a viable avenue to pursue.

In popular culture

 * Flechette weapons see heavy use in science fiction, particularly in cyberpunk settings like William Gibson's Sprawl trilogy. They are called by a variety of names, including fletchers, needlers, needle guns, or named as 'flechette' variations of realistic weaponry (e.g. flechette rifle) . They are most often employed as pistols. They are typically characterized as having short range, high impact firing capabilities.
 * Flechette weapons are standard weaponry among the human survivors in Terry Brooks's Genesis of Shannara series, ranging from small pistols like the Tyson 33 Flechette to large vehicle-mounted weapons capable of destroying guard towers. These flechettes resemble extremely powerful shotguns more than actual flechettes.
 * In volume 26 The Attack of the book series Animorphs, the Howler soldiers sent to eliminate the Animorphs using an assortment of weapons, including flechette guns.
 * Many video games feature guns that fire flechettes, including but not limited to Turok: Evolution, Battlefield 2142, Star Wars Jedi Knight II: Jedi Outcast, Star Wars: Battlefront 2, Half-Life 2: Episode Two, Hexen, Hitman: Blood Money, Unreal Tournament, and Team Fortress 2.
 * The video game "Quake" features a flechette gun called a "nailgun"
 * Additionally, an early novel by Douglas Preston and Lincoln Child features a flechette small arm on a naval vessel.
 * A common ammo for J.B. Dix a character in James Axler's Deathlands novels.