The term ''Big Five'' Weapons was given to a special Project by The US Army Chemical Corps. in Ft. Detrick, Maryland. The Project ran from 1950 to 1969. The goal was to produce Chemical and Biological weapons which could be deployed by the Basic Infantry Combat Soldier in a Nuclear, Biological and Chemical (NBC) environment. The result was (5) such devices. Designed and stored, it is not known of any of these devices were ever deployed in actual field operations by The US Army.
The 1st Device was The M1 Biodart. This was a 7,62mm modified Rifle Round (Sabot) into which was placed one of two Neurotoxins. The ideology was that a Soldier could fire and hit with an Enemy or strike a fixed fighting position (''foxhole''). The Round would ''detonate'' on impact, releasing The Toxin. This would obviously kill the initial target and poison many more. Over 5,000 M1 Round were eventually destroyed in the 1970s.
The 2nd Device was The M2 Separable Bullet. Like The M1, The M2 was designed to explode on impact and release a toxic ''cloud'' of Neurotoxin or Anthrax. Caliber varied. Over 72,000 M2s were destroyed in the 1970s.
The 3rd Device created was The M4 Disseminator. This was a Grenade type weapon which was thrown or launched, upon which – impact released a cloud of Toxic Gas. 40,000 M4 were destroyed as well.
The 4th Weapon created was The M5 Depositor. These were large canister which could be placed (buried or time fused), along a Road. They would be triggered to explode, release Toxic Gas among an Enemy Vehicle Convoy. Almost 3,000 were destroyed.
The last was The M32 Disperser. A pressurized bottle of Nerve Gas, this was a 2-gallon solution carried in a specialized backpack. They were to be deployed front the pack, on a Hill or Mountain – downwind. The deadly released Gas would cover a much greater area. 400 M32s were destroyed in the 1970s as well.