The excellent ballistic performance and armor-piercing potential of flechettes have made the development and integration of this class of munition attractive to small-arms manufacturers. A number of attempts have been made to field flechette-firing small arms. Work at
Johns Hopkins University in the 1950s led to the development of the direct injection antipersonnel chemical biological agent (DIACBA), where flechettes were grooved, hollow pointed, or otherwise milled to retain a quantity of chemical or biological warfare agent to be delivered through a ballistic wound. The initial work was with the nerve agent
VX, which had to be thickened to deliver a reliable dose. Eventually this was replaced by a
highly toxic carbamate insecticide. The US Biological Program also had a microflechette to deliver either
botulinum toxin A or
saxitoxin, the M1 biodart, which resembled a 7.62 mm rifle cartridge. The USSR had the
AO-27 rifle as well as the
APS amphibious rifle, and other countries have their own flechette rounds. A number of prototype flechette-firing weapons were developed as part of the long-running
Special Purpose Individual Weapon (SPIW) project. The
Steyr-Mannlicher ACR rifle was a prototype flechette-firing assault rifle built for the US Army's
Advanced Combat Rifle program of 1989–90. A variation of the flechette addressing its difficulties is the
SCMITR, developed as part of the
Close Assault Weapon System, or CAWS, project. Selective-fire shotguns were used to fire flechettes designed to retain the exterior ballistics and penetration of standard flechettes, but increase wounding capacity through a wider wound path.
Shotguns During the Vietnam War the United States employed 12-
gauge combat shotguns using flechette loads. These plastic-cased shells were issued on a limited trial basis during the Vietnam War. Cartridges manufactured by the
Western Cartridge Company contained 20 flechettes, each long and weighing ;
Federal Cartridge Company rounds contained 25. The flechettes were packed in a plastic cup with granulated white
polyethylene to maintain alignment with the bore axis, and supported by a metal disk to prevent penetration of the over-powder wad during acceleration down the bore. The tips of the flechettes were exposed in the Federal cartridges, but concealed by a conventional star crimp in WCC's cartridges. The flechettes demonstrated flatter trajectories over longer ranges than spherical buckshot, but combat effectiveness did not justify continued production. ==Rocket and artillery use==