SCMITR was part of an experimentalmilitaryshotgunammunition created in the 1970s byAAI Corporation. It was a variation onflechette ammunition, but instead of containing a bundle of tiny needle-likesteeldarts, the cartridge contained a stack ofrazor-edged stampedsheet-metalarrow shapes designed to flyaerodynamically. It was considered to be very promising (in terms oflethality and effective range) but prohibitively expensive to manufacture, so it has never been mass-produced.[1][2]
SCMITR was part of theCAWS (Close Assault Weapon System) program, which investigated ~20 mmsmoothbore weapons (basicallycombat shotguns) designed to be effective to ranges of 150 metres against combatants wearingbody armor. Flechettes, with their high sectionaldensity, 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 twofins, 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 bookThe World's Fighting Shotguns, shows a SCMITR shell clearly marked as a 20gauge, smaller than the nominal 12 gauge bore used by the AAI CAWS entry.