Planned to fight Vietcong insurgency, the Mobile Guerrilla Forces (MGF) evolved out of the special reconnaissance projects—Projects Delta, Omega, and
Sigma—established in 1965 and 1966. Each MGF consisted of a 12-man A-Team of Special Forces, a 150-man mobile guerrilla company, and a 34-man
combat reconnaissance platoon. The MGF operated for extensive periods of time in Communist-controlled regions of South Vietnam and Cambodia. Essentially
they were hit-and-run units giving the North Vietnamese and Vietcong a taste of their own tactical medicine. The MGF operations were known
as "Blackjack Missions" and existed between October 1966 and July 1967, when they became part of the Mobile Strike Forces.
And Other Vietnam War Short Stories
http://www.vietnamwar.net