Description
The cartridge is an improved fuzeless pyrotechnic initiated 20mm HE cartridge. The projectile consists of a heavy walled steel body charged with explosive mix and an incendiary mix, and an aluminum nose charged with another incendiary mix. The projectile also has safe and arming (S&A), tracer, and self-destroying which is initiated by heat from combustion of the tracer composition. The lack of fuze permits an enhanced aerodynamic ogive shape which results in a reduction in drag factor and reduced time of flight, thereby extending the effectiveness of the VADS from 1,200 meters to 2,000 meters against aircraft targets. The M940 will replace the 20mm M246 HEI-TSD as the primary air defense cartridge for the VADS and any of its improved versions.
The projectile consists of a steel body charged with a HE mix, Composition A-4 (MILC-440), and an incendiary mix, Type I (equivalent I-68). The projectile has an aluminum nose charged with Type II incendiary (equivalent I-136). The hardened forebody of the projectile provides for defeat of lightweight armor (3/8 RHA at well over 500 m). The incendiaries provide a built-in delay when initiated on the thin skin of an aircraft, and the projectile explodes approximately 1 foot behind the skin. The M94 cartridge, therefore, is primarily intended for air defense but has a secondary roll against light armored vehicles. The M940 contains a chemical S&A intended to reduce the probability of functioning on a 0.04 aluminum plate at 1 meter from the muzzle. When initiated, all projectile fragments go forward.
Hazardous Components
Tracer - modified R505
Primer - electric M52A3B1
Explosive - Comp A-4 (4 g)
Incendiary - Type I (1.2 g), Type II (3 g), potassium perchlorate (0.2 g)
Propellant - WC 866 (37 g, 1.32 oz)
See Also
Cartridge, 20mm HEI-T SD, M246, M246A1
Source(s)
TM 43-0001-27, Small Caliber Ammunition (chg 7, 2004)
