55 years ago today.
Official caption, 16 February 1968. “Bird’s Eye View: The Song Cau Bien river as seen by Marines manning a 106mm recoilless rifle atop Marble Mountain”
(official USMC photo by Corporal Bob Leak) From the Jonathan Abel Collection (COLL/3611), Marine Corps Archives & Special Collections.
The M40 recoilless rifle, which entered service in 1955 as a result of lessons learned in the Korean War against both Soviet-made T-34s and Chinese human wave attacks against defensive positions, could pinch-hit between anti-tank M344A1 HEAT rounds capable of penetrating over 400mm of armor (the turret face and mantlet of the T-34-85 were only 90 mm thick and the follow-on T-54/T-55 had 205mm of armor on its turret front) and M494 APERS-T rounds, with the latter being nothing but modernized Napoleanic-era canister shot.
“C.M. Burks Directs 106mm Recoilless Rifle Fire, 1969. “Fire Away: 2d Battalion, 5th Marines [2/5] Sergeant Major C. M. Burks (Monticello, Arkansas) directs 106mm recoilless rifle fire during a two-day battle in the Arizona Territory; about 17 miles southwest of Da Nang. During the running battle, Marines, supported by artillery and air strikes, killed 219 enemy soldiers (official USMC photo by Sergeant J. A. Mullins).”
Weighing just over 400 pounds, it could be tripod mounted in just about any position you could fit a heavy machine gun in (provided it had a clear backblast area) while still being able to reach out with an effective range of 6,800 meters with the right load.
The lightweight meant it could be helicoptered in from offshore assault ships and wrestled into place my a few Marines with strong backs, the Vietnam-era version of the old landing gun, if you will.
“With Loving Care: Lance Corporal Ronnie N. Rentz, 20 (Augusta, Georgia) of the 3d Battalion, 1st Marines [3/1], applies a protective coat of oil to his 106mm recoilless rifle while aboard the helicopter assault ship USS Valley Forge (LPH-8) as part of the Special Landing Force along the coast of Vietnam (official USMC photo by M. J. Coates).” From the Jonathan F. Abel Collection (COLL/3611) at the Archives Branch, Marine Corps History Division
“Marines Move a 106mm Recoilless Rifle, February 1968 Fire Power: Leathernecks move a 106mm recoilless rifle during heavy fighting in Hue. The team are members of A Company, 1st Battalion, 1st Marines [A/1/1]” (official USMC photo by Sergeant Bruce A. Atwell) From the Jonathan F. Abel Collection (COLL/3611) at the Archives Branch, Marine Corps History Division
Robert Sepulveda Cleans His 106mm Recoilless Rifle, 16 February 1968 “Valley Protector: Corporal Robert Sepulveda, 20 (Florence, Arizona), carefully cleans his 106mm recoilless rifle atop Marble Mountain (official USMC photo by Sergeant Bob Leak).”
It could also be transported via mules (the mechanical type) and jeeps as well as the peculiar M50 Ontos which mounted six M40s full-time.
“Rough Going: Leathernecks of the 1st Marine Division’s 1st Marine Regiment find the going rough in ‘Dodge City’ as they attempt to maneuver a ‘mechanical mule’ bearing 106mm recoilless rifle across rugged terrain. The Marines are participating along the Vietnamese Army elements and Vietnamese rangers and Korean Marines in Operation Pipestone Canyon, in the Dodge City-Go Noi Island area 12 miles south of Da Nang (official USMC photo by Sergeant A. V. Huffman).”
While the Marines would eventually hang up their M40s once TOW came along by the mid-1970s, the much-loved and very simple 106 is still in active service with more than a dozen users around the world and continues to pop up in conflict zones.
Compañía Antiblindaje “Karut” del Destacamento Motorizado N°14 “Aysén” with M40 106mm recoilless rifle Aug 2021