Recoilless Weapons: From the Mountains of Korea to the Rivers of Vietnam

This 75mm shell currently on display at the Hampton Roads Naval Museum is designed to be fired from the Chinese Type 52 recoilless rifle. The perforations on the case allow the propellant gases to escape during firing, which then vent through the back of the rifle’s breech and eliminate any recoil.  This Chinese-made high-explosive 75mm round was captured in 1967 by an intelligence platoon of the Republic of Vietnam Navy (VNN) in the Rung Sat Special Zone (a partial map of which is in the background of the photograph), a vast mangrove swamp known to harbor Communist insurgents for most of the Vietnam War.  A U.S. Naval Forces Vietnam Zippo lighter, monogrammed to be presented by Admiral Elmo Zumwalt, is shown for scale. (M.C. Farrington)

By A.J. Orlikoff
Hampton Roads Naval Museum Educator

Prologue: Korea, 1952

U.S. Army Staff Sgt. Donald Kirkpatrick poses for a photo during his time in the Korean War. Serving from October 1951 to July 1953, the Mansfield, Ohio native was drafted into the Army and received additional special training in heavy weapons, including with the M20 recoilless rifle. The younger brother of a Battle of the Bulge veteran, Kirkpatrick served until being recalled to the United States and honorably discharged in July 1953. An accomplished plumber and volunteer firefighter, Kirkpatrick never forgot his experiences in the Korean War. (Mansfield [Ohio] News Journal)

Army Staff Sergeant Donald Kirkpatrick, while assigned to the 2nd Battalion, 23rd Infantry Regiment, 2nd infantry Division, was stationed at a defensive position on a mountaintop along the 38th parallel. With Korean People's Army (North Korean) soldiers holding a neighboring mountain, it was Kirkpatrick’s job as a heavy weapons observer to ascertain how best to bombard the North Korean position. Wary of the North Korean artillery which had previously bombarded their position and killed one of his friends, Kirkpatrick came up with a new plan.

American army soldiers fire a M20 recoilless rifle during the Korean War. While designed to be a light infantry anti-tank weapon, the M20 was ineffective at penetrating the thick armor of Soviet built T-34 tanks. Army units adapted and utilized the light weight of the recoilless rifle as a portable infantry support weapon. In this purpose, the M20 excelled as its light weight allowed American units to effectively suppress and destroy enemy bunkers and entrenched positions.(U.S. Army photograph)

Kirkpatrick realized that one of their heavy weapons, an M20 75-mm recoilless rifle, had allowed the North Korean artillery to zero in on their position as the powerful back blast kicked up dust plumes that could be seen from miles away. Kirkpatrick remembered, “It [the M20] was a direct-fire weapon and they [North Korean troops] could see where we were because of it [back blast]. Me and a couple of other sergeants, we came up with the idea of setting up an 82-millimeter mortar a ways back from the recoilless crew. When the North Koreans would fire on the recoilless, we’d start dropping mortars on them. The enemy couldn’t see us at all because we were down behind the rifle.” Turning a weakness of the M20 into strength, the men of the 23rd bombarded the North Korean artillery position with mortar fire, silencing the North Korean artillery, at least for another day. Kirkpatrick never forgot his experiences serving in the Korean War using the M20 recoilless rifle.

An assortment of American arms, including bazookas, captured during the Korean War on display at the Victorious Fatherland Liberation War Museum in Pyongyang, Democratic People's Republic of Korea (North Korea) in April 2010. The North Koreans' allies from the People's Republic of China studied and replicated such arms, which included American recoilless rifles, which ultimately found their way into the Democratic Republic of Vietnam (North Vietnam) and were used by their armed forces as well as Viet Cong cadres operating in the Republic of Vietnam (South Vietnam). (John Pavelka/ Flickr/ Wikimedia Commons)   

More than a decade later, American servicemen fighting another war against Communists also experienced the M20 recoilless launcher, but this time it was used by the enemy.

Vietnam: Recoilless Weapons Rebound

American and Army of the Republic of Vietnam (ARVN) forces were fighting a much more unconventional type of war in Vietnam than in Korea, countering an insurgency. The operational challenges associated with this type of warfare were numerous and the Viet Cong (VC) were not going to make it easy.  VC forces, outmatched by superior American and ARVN forces, employed ambush tactics against Army and Navy forces with whatever weapons they could get their hands on.

Although easy to use, the Chinese Type 52/56 did require training to use effectively. In this photo, Viet Cong recruits pose for a photo with a Chinese Type 52 while being trained to use the weapon. Notice that the Type 52 is angled for use as an indirect fire weapon, lobbing shells at a high trajectory (like a mortar) to hit targets hundreds of yards away. The man 2nd from the right is holding a shell for the weapon.  (Australian War Memorial)

The VC used a number of Soviet and American-designed weapons such as the RPG-7, the B-40, and the Type 51 (a copy of the American bazooka) to combat U.S. Navy and Republic of Vietnam Navy (VNN) riverine assets.  Many if not most were made in the People's Republic of China.  One of them would have been very familiar to Kirkpatrick.  The 75-mm recoilless rifle round on display in the exhibit, The 10,000 Day War at Sea, the U.S. Navy in Vietnam, 1950-1975, is made for a Chinese Type 52 Recoilless Rifle, an exact copy of the American M20 Recoilless Rifle that Kirkpatrick used in Korea.

Found among the photographs Army Staff Sgt. Ernest W. Payne of Charlotte, North Carolina, took during the Vietnam War is this captured recoilless rifle at an unidentified camp in South Vietnam.  Although it bears a passing resemblance to the American M18 57-mm recoilless rifle, which was used during the Korean War, it is most likely a Chinese Type 65 82-mm smoothbore recoilless gun copied from the Soviet B10. (Ernest W. Payne Papers,VW 22, Vietnam War Papers, Military Collection, State Archives of North Carolina, Raleigh, NC)

An unidentified U.S. Army Soldier leans on a captured enemy recoilless rifle (Most likely a Chinese Type 65) from the photo collection of Staff Sgt. Ernest W. Payne, who served at Headquarters and Headquarters Company, 2nd Battalion, 7th Calvary, 1st Air Calvary Division from 1967 to 1968. (Ernest W. Payne Papers,VW 22, Vietnam War Papers, Military Collection, State Archives of North Carolina, Raleigh, NC)

Most rocket weapons used by Viet Cong fighters were recoilless launchers.  Known as Dai-bac Khong Giật (DKZ) by Viet Cong fighters, recoilless rifles and launchers were an integral component of their war effort.  Recoilless weapons were effective and easy-to-use rocket launchers capable of accurately launching an explosive warhead anywhere, depending on the rifle and expertise of the user, from 100 to 400 meters away.  As the name suggests, recoilless launchers were ingeniously designed to minimize recoil through a forceful ejection of gas from the rear of the weapon.  This creates reverse thrust, counteracting the recoil from the launch of a projectile.  This system allows the construction of light-weight, portable launchers without bulky recoil-countering components.

German soldiers in World War II, seen here after firing the 10.5-cm Leichtgeschütz 40, were the first force to widely utilize recoilless rifles in combat. Translating to “Light Gun 40,” the 7.5-cm Leichtgeschütz 40 was first used during the German invasion of Crete, where 22,000 Fallschirmjäger paratroopers attacked British and Greek units on Crete. It was the first mass airborne invasion in history and, despite heavy losses, the German paratroopers succeeded in accomplishing their objectives. Due to the success of the 7.5-cm Leichtgeschütz during the invasion, other recoilless rifle variants were produced such as the larger 10.5-cm variant which were organized into artillery units as opposed to an infantry support role. Favored by the Fallschirmjäger paratroopers and Gebirgsjäger mountain troops for their light weight, recoilless rifles proved to be a viable and effective weapon during World War II. (Wikimedia Commons)

The first recoilless rifles were designed by German and Soviet weapon designers in the 1930s. In particular, the German Leichtgeschütz 40 proved to be particularly effective, with the 7.5 cm variant providing critical light infantry support to German paratroopers during the invasion of Crete. The German designs were loosely copied by American manufacturers and were adopted by the Army towards the end of World War II, including in the form of the M20 recoilless rifle. Firing a spin-stabilized 75-mm HEAT round, the M20 first saw widespread service during the Korean War as a light infantry anti-tank weapon. The M20 proved to be ineffective at penetrating the thick armor of Soviet built T-34 tanks but Army units adapted and utilized the light weight of the recoilless rifle as a portable infantry support weapon, using it effectively against enemy bunkers and artillery positions.

The United States quickly produced much more effective anti-tank weapons, such as the M40 recoilless rifle and the M72 LAW. Largely obsolete by the time of the Vietnam War, the M20 suited the uses of the Viet Cong well. While the M20 was ineffective at penetrating the thick armor of Soviet tanks, it was perfectly capable of taking on the unarmored fiberglass hulls of Navy river patrol boats (PBRs) on the rivers of South Vietnam. China produced unlicensed copies of the M20 in the form of the Chinese Type 52 after capturing M20s during the Korean War. Identical to the M20, Type 52 recoilless rifles were produced in their hundreds and sent down the Ho Chi Minh Trail.

The Type 52 was extensively used by People's Army of Vietnam (North Vietnamese) and Viet Cong fighters during the Vietnam War.  Its advantages were the same as the widely-used B-40 launcher; The Type 52 was light-weight, easy to transport, easy to use, versatile, and packed a powerful punch. With a range of up to 400 meters and a muzzle velocity of 300 meters per second, the Type 52 was more than capable of ambushing Navy riverine forces from the banks of rivers, canals, and waterways. Breech loaded and fired from a tripod, a trained crew of two to three guerrillas could quickly fire multiple shells at an enemy. The Type 52 could also be used in an indirect fire role, with a kilometer range when lobbing high-explosive shells at high arc of trajectory into American or ARVN bases. The Chinese Type 56, another M20 variant, improved on the original M20 design with the addition of a fin-stabilized warhead as opposed to a spin-stabilized one, adding to its armor piercing capability, accuracy, and range. The weakness of the Type 52/56 was the same that Kirkpatrick had observed; the powerful back blast of the weapon was highly visible, exposing the location of the weapon and its crew.

The original record photograph of the 75-mm recoilless rifle round. (Naval History and Heritage Command Curator Branch)

The 75-mm Type 52 shell on display stands as poignant reminder of the paradoxical nature of the Vietnam War.  An American weapon was copied and produced by a Cold War rival and shipped to a Communist guerilla force fighting an unconventional asymmetric war against American forces. VC guerillas effectively used the Type 52 and other recoilless weapons to engage American riverine forces. Although the VC were defeated time and time again on the battlefield by American and ARVN forces, their ability to efficiently resupply with cheap and reliable weapons like the Type 52/56 enabled them to continue fighting throughout the conflict.

The display area showing the Chinese-made 75-mm recoilless round currently on display in the Riverine section of the Hampton Roads Naval Museum's new exhibit, The Ten Thousand-Day War at Sea, The U.S. Navy in Vietnam, 1950-1975. (M.C. Farrington)