|Branch|| National Liberation Front (until 1976)|
People's Army of Vietnam (1976-present)
|Role||Guerrilla (until 1976)|
Regular infantry (1976-present)
|Part of||5th Infantry Division (Vietnam)|
On 11 November 1965, the Regiment ambushed the ARVN 52nd Rangers near Kim Hai hamlet, in the village of Phuoc Hoa on Route 15, in Phuoc Tuy Province and inflicted heavy casualties upon the ranger battalion.
Part of the Regiment fought initially against the 173rd Airborne Infantry Brigade between 24 May and 4 June 1966 during Operation Hardihood.American casualties during that operation were 23 killed and 160 woundedand 48 Viet Cong soldiers were reported to have been killed."American casualties during that operation were 23 killed and 104 wounded for a VC body count of 48."
The Regiment or its battalions participated alongside D445 Provincial Mobile Battalion in the Battle of Long Tan against Australian forces from D Company, 6th Battalion, Royal Australian Regiment. According to the D445 Battalion political officer, the unit provided "guides for the units that mortared the Task Force" at Nui Dat base on 17 August 1966. A Viet Cong medic, Chung, reported that three of the 275th Regiment RCL detachment involved were killed in the Australian counter-battery fire and were buried nearby. Casualties among the Australians in the bombardment were 22 wounded. During the battle an 80-strong Vo Thi Sau civil labour company commanded by Chin Phuong, comprising mainly women and children, lent support by evacuating and treating the casualties. Vietnamese dead, according to Viet Cong and NVA histories were 47 killed. (Source: The Battle of Long Tan: NVA/VC Forces - Revisited. By Ernest Patrick Chamberlain. August 2013.) Australian veterans and historians, in the main, claim that at Long Tan the 275 Regiment and D445 Battalion suffered heavy casualties, with the official Australian body count reported to be 245 Vietnamese killed. Only one member of D445 was captured at Long Tan (reportedly a 57 mm RCL gunner); and two members of 275 Regiment were captured who declared themselves to be members of "Doan 45" as their cover story. Several 275th Regiment soldiers received medals, letters of appreciation and commendation certificates for their part in the fighting. Estimates from official history records from the D445 Battalion indicate between 30-47 KIA total including other regiments.
The next major contact took place on 2 December 1966, when a US resupply convoy was attacked by the 275th Regiment south of Gia Ray. In this battle, the U.S. forces involved claimed to have killed at least 99 Viet Cong soldiers, while a sergeant from the 27th Engineer Battalion was killed and 22 were wounded in the Black Horse Regiment.
During the start of the Tet Offensive, the 274th and 275th Regiments of the 5th Viet Cong Division took part in the attacks on Bien Hoa, northeast of Saigon on 18 February 1968.
In November 2006, Australian Prime Minister John Howard paid respect to the Vietnamese authorities, laying a wreath at the Go Cat Military Cemetery in Ba Ria-Vung Tau Province where some 2000 former enemy combatants (mainly 5th and 9th NVA Divisions soldiers) are buried.
In 2010, as part of Operation Wandering Souls, Bob Hall and Derrill de Heer, both Vietnam veterans who are now academics at the University of New South Wales and the Australian Defence Force Academy, presented to the Veterans Association of Ba Ria-Vung Tau province, a list containing the full names, ranks and unit numbers of 535 Vietnamese soldiers buried by Australians in the province.
- Wilkins 2011, p. 255.
- Rowe 1987, pp. 62–63.
- McNeill 1993, p. 222.
- Lyndon B. Johnson: "Presidential Unit Citation Awarded to the 52d Ranger Battalion, Army of the Republic of Vietnam, and Attached Units", November 18, 1966. Online by Gerhard Peters and John T. Woolley, The American Presidency Project.
- "Part of the 275 supported D445 Bn and inflicted heavy casualties on the 173rd Airborne brigade in Long Phuoc" Long Tan: The Other Side of the Hill Archived 2015-09-24 at the Wayback Machine
- "In helping the Australian Task Force to become established, The Americans had suffered 23 killed and a 160 wounded."OPERATION HARDIHOOD
- Dennis et al 2008, p. 556.
- Chamberlain 2011, p. 44.
- Bruce Horsefield (Director/Producer), Long Tan: The True Story, DVD, 1993
- Chamberlain 2011, p. 42.
- Chamberlain 2011, p. 45.
- Chamberlain 2011, p. 47.
- Walter 1997, p. 79.
- Conboy & Bowra 1991, p. 13.
- Howard recalls sacrifice and unhappy return of Long Tan troops
- Godfrey, Calvin; Hung, Minh (6 April 2012). "Finding peace, decades after war". Thanh Nien News. Retrieved 18 December 2013..
- Chamberlain, Ernest (2011). The Viet Cong D445 Battalion: Their Story. Point Lonsdale, Victoria: Ernest Chamberlain. ISBN 9780980562347.CS1 maint: ref=harv (link)
- Conboy, Kenneth; Bowra, Kenneth (1991). The NVA and Viet Cong. London: Osprey Publishing. ISBN 9781855321625.CS1 maint: ref=harv (link)
- Dennis, Peter; et al. (2008). The Oxford Companion to Australian Military History (Second ed.). Melbourne: Oxford University Press Australia & New Zealand. ISBN 978-0-19-551784-2.
- McNeill, Ian (1993). To Long Tan: The Australian Army and the Vietnam War 1950–1966. The Official History of Australia's Involvement in Southeast Asian Conflicts 1948–1975. Volume Two. St Leonards, New South Wales: Allen and Unwin. ISBN 1863732829.CS1 maint: ref=harv (link)
- Rowe, John (1987). Vietnam: The Australian Experience. North Sydney: Time-Life Books Australia. ISBN 0949118079.CS1 maint: ref=harv (link)
- Walter, Peter L. (1997). Black Horse Regiment in Vietnam, 1966-1972. Dubuque, Iowa: Kendall/Hunt Publishing Company. ISBN 9780787239015.CS1 maint: ref=harv (link)
- Wilkins, Warren (2011). Grab Their Belts to Fight Them: The Viet Cong's Big-Unit War Against the U.S. Annapolis: Naval Institute Press. ISBN 9781591149613.CS1 maint: ref=harv (link)