grenade often became a more useful weapon than the rifle. Spanish rifle grenades were sourced from Instalaza, but in due course, the Dilagrama m/65 was more commonly used, using a derivative of the M26 grenade made under licence by INDEP, the M312. For the general purpose machine gun role, the German MG42 in 8mm and later 7.62mm NATO caliber was used until 1968, when the 7.62mm m/968 Metralhadora Ligeira became available. To destroy enemy emplacements, other weapons were employed, including the 37 mm (1.46 in), 60 mm (2.5 in), and 89 mm (3.5 in.) Lança-granadas-foguete (Bazooka), along with several types of recoilless rifles.Abbott, Peter and Rodrigues, Manuel, Modern African Wars 2: Angola and Mozambique 1961–74, Osprey Publishing (1998), p. 18 Because of the mobile nature of counterinsurgency operations, heavy support weapons were less frequently used. However, the m/951 12.7mm (.50 caliber) U.S. M2 Browning heavy machine gun was used in ground and vehicle mounts, as were 60mm, 81mm, and later, 120mm mortars. Artillery and mobile howitzers were used in a few operations. Mobile ground operations consisted of patrol sweeps by armored car and reconnaissance vehicles. Supply convoys used both armored and unarmored vehicles. Typically, armored vehicles were placed at the front, center, and tail of a motorized convoy. Several armored cars were used, including the Panhard AML, Panhard EBR, Fox and (in the 1970s) the Chaimite. Unlike the Vietnam War, Portugal's limited national resources did not allow for widespread use of the helicopter. Only those troops involved in coups de main attacks (called golpe de mão in Portuguese)—mainly Commandos and Paratroopers—deployed by helicopter. Most deployments were either on foot or in vehicles (Berliet and Unimog trucks). The helicopters were reserved for support (in a gunship role) or medical evacuation (MEDEVAC). The Alouette III was the most widely used helicopter, although the Puma was also used with great success. Other aircraft were employed: for air support the T-6 Texan, the F-86 Sabre and the Fiat G.91 were used, along with a quantity of B-26 Invaders covertly acquired in 1965; for reconnaissance the Dornier Do 27 was employed. In the transport role, the Portuguese Air Force originally used the Junkers Ju 52, followed by the Nord Noratlas, the C-54 Skymaster, and the C-47 Skytrain (all of these aircraft were also used for Paratroop drop operations). From 1965, Portugal began to purchase the Fiat G.91 to deploy to its African overseas territories of