Recoilless rifles were usually employed to fire from the flanks of NVA units or from high points offering concealment and longer fields of fire.
57mm Recoilless Rifle (CHICOM Type 36)
The recoilless rifle that had the best mobility was also the lightest, the 57mm. The 57mm recoilless rifle weighed about 52-lbs and could be fired from the shoulder or affixed to a machine gun tripod for greater accuracy. Maximum effective range was about 1500 yards and it could destroy point targets although it had little effect on armored fighting vehicles. The Type 36 was a copy of the US 57mm M18 recoilless rifle.
This weapon could be fired from the shoulder, from its monopod, or from a tripod. The outstanding identifying feature of this weapon was the long, cylindrical monopod below the telescopic sight, the two protruding handles at the breech end, and the peculiarly shaped tripod.
75mm recoilless rifle (CHICOM Type 52/56)
Particularly favoured by the NVA and VC, the Type 52 combined firepower with light weight and could fire both PRC (Chicom) and US ammunition. This weapon was frequently used in attacks on fire bases and other strong-points. This was a breech-loading, portable weapon, designed to be fired from a machine gun tripod. The barrel and breech of the 52/56 weapon were copied from those of the US 3.5inch M20 rocket launcher.
The longer ranged 75mm RR weighed about 130-lbs and had to be carried by two or more crew. It fired high explosive rounds to a maximum range of 7300 yards and HEAT shells to an effective range of 875 yards. The long dismantling time and heavy weight of the weapon made using it in standoff attacks involved exposing the crew to a lot of risk from return fire or air attack. However, it was a very effective anti tank weapon.
Soviet B-10 (RG82) 82mm recoilless gun
Used by the Viet Cong, the B10 was a smoothbore, breech-loaded and percussion-fired gun mounted on a tripod-supported pedestal. The trigger and bolt being accommodated in a pistol-grip located above and to the right of the tripod mount, whilst the optical sight is on the opposite side in front of a rectangular, perforated guard. The gun was designed to be transported in a truck or armoured personnel carrier, but can be towed by its four-man crew on its small two-wheeled carriage using the conspicuous tow-bar fitted below the muzzle. The small castor wheel below the tow-bar is designed to prevent the muzzle touching the ground while the gun is being maneuvered or set up for firing on the tripod. The latter can be adjusted to give either a low silhouette or a better field of view, but the weapon can, if necessary, also be fired whilst still on the wheeled mount. A rate of fire of 6-7 rpm is attributed to the B10.
Recognition features were the two-piece tube, the detachable wheels, the multi-perforated guard on the left side, and the towing handle.
Czech T-21 (Tarasnice) 82mm recoilless gun
The Czech T21 recoilless anti-tank gun was a very versatile weapon, capable of being fired from its small two-wheel carriage, from the shoulder or from a fixed mount.
It was a smooth-bore weapon, firing a shaped-charge fin-stabilised HEAT round, which is breech-loaded, and fired electrically - as with the P27 anti-tank grenade launcher, the trigger action works a magneto. To cope with the direct and indirect fire capability, the T21 was equipped with ordinary iron sights graduated in 50m intervals and also a telescopic sight graduated at 100 m intervals.
The HEAT round, 2.1 kg in weight, could penetrate up to 230mm of armour at an effective range of 300m if the target was moving, and up to 650m if the target was stationary. Rate of fire was about 5rpm, but this was adversely affected by the absence of a used round extractor in the breech, which had to be cleared manually with the aid of an asbestos glove.
The T21 was usually transported in a truck or armoured personnel carrier, but could be towed for short distances using the long tubular towing handle, normally kept folded over the top of the tube.
Soviet B-11 (RG107) 107mm recoilless gun
Use by both the NVA and VC, the B11 (or RG107) was the biggest recoilless gun manufactured by the USSR, having been developed (along with the B10) from knowledge gained from United States weapons captured during the Korean War.
Whilst the B11 was designed primarily as an anti-tank gun, able to pierce 350mm of armour at 450m, it was light and mobile enough on its two-wheeled carriage to be maneuvered in battle by its five-man crew using the light tow-bar attached below the muzzle. Although the B11 can, like the smaller but similar B10, be fired from its wheeled mount, the motor-car-type wheels were awkward and were often removed whilst the gun was raised on its tripod.
The two main recognition features of this weapon were the tripod which, while traveling, was spread with the front leg attached to the tube and the two rear legs raised and carried at an angle to the rear, and the limber loop above the muzzle by which the gun was connected to its towing truck.
The B11 is breech-loaded, using a shaped-charge, fin-stabilised HEAT or HE round. The PBO4 direct and indirect fire sight was mounted high and centrally on the gimbal mounting of the barrel.
NVA Regimental Recoilless Rifle Company
US Army Military Assistance Advisory Group Vietnam (MAAG) - Lessons Learned No. 71 Countermeasures Against Standoff Attacks (March 1969)
Secrets of the Viet Cong J W McCoy, Hippocrene Books 1992, ISBN 0-7818-0028-5
Inside the VC and the NVA Michael Lee Lanning & Dan Cragg, Ivy Books 1994, ISBN 0-8041-0500-6
Vietnam Weapons Handbook, David Rosser-Owen, Patrick Stephens Limited, 1986, ISBN 0-85059-838-9
Infantry Weapons of the World, Christopher F. Foss and T.J.Gander, Ian Allen Ltd., 1977, ISBN 07110-0734-9
'The Vietnam Experience', Orbis Magazine Collection
Warsaw Pact Infantry and its Weapons, edited by J.I.H. Owen, Brassey's Publishers Ltd., 1976, ISBN 0-904609-03-0
Weapons and Tactics of the Soviet Army, David C. Isby, Janes Publishing, ISBN 0-7106-0089-5