No. 68 AT grenade
| Grenade, rifle No. 68 /AT | |
|---|---|
 The Mark 1 No. 68 rifle grenade, shown with the nose facing left | |
| Type | Anti-tankrifle grenade |
| Place of origin | United Kingdom |
| Service history | |
| In service | 1940–1945 |
| Production history | |
| Designed | 1940 |
| Variants | Mk 1 to Mk VI |
| Specifications | |
| Mass | 894 grams (31.5 oz) |
| Diameter | 2.5 inches (64 mm) |
| Effective firing range | 70 yd (64 m) |
| Filling | Lyddite,PentoliteorRDX/beeswax |
| Filling weight | 156 grams (5.5 oz) |
Detonation mechanism | Impact |
TheGrenade, Rifle No. 68 / Anti-Tankwas a Britishanti-tankrifle grenadeused during theSecond World Warand was one of the first operational weapons to utilise theshaped chargeprinciple.
Design
[edit]
British research into shaped charges in theinter-war periodbrought about some useful progress but did not result in any weapons. Development of the grenade started in late 1939, after a demonstration arranged for a British military commission of a series of anti-tank rifle grenades and artillery warheads at the Swiss Army Proving Ground atThunin Switzerland, which had been designed byHenry Mohaupt.Guessing that Mohaupt's weapons were using the hollow charge principle, the British abandoned negotiations and began development of a rifle grenade based on their own previous work.[1]
The No. 68 has some claim to have been the firsthigh-explosive anti-tank(HEAT) device in use. The design of the warhead was simple and was capable of penetrating 52 mm (2.0 in) of armour.[2]
Thefuzeof the grenade was armed by removing a pin in the tail which prevented thefiring pinfrom flying forward. The grenade was launched from a rifle cup. The simple fins gave it some stability in the air and, provided the grenade hit the target at the proper angle (90 degrees), the charge would be effective.Detonationoccurred on impact, when a striker in the tail of the grenade overcame the resistance of a creep spring and was thrown forward into a stabdetonator.[3]
The grenade was fired, as was the No. 36MMills bomb,from a specially adaptedLee-EnfieldRifle No. 1 EY,[a]often converted from a rifle that was unfit for general use and had been marked "DP" fordrill purpose.The converted rifles were strengthened by adding an extra bolt to secure the breech mechanism to the stock, and by a cord binding which was fastened around the forestock. A specialBallistitehigh-explosive cartridge was required to propel the grenade. The grenade itself was held in place by the2+1⁄2inches (64 mm) discharger cup No. 1 Mk I. With the weapon's introduction into Home Guard use, the Adaptor No. 1 and the Discharger No. 2 Mk I were introduced, which allowed grenades to be launched from theM1917 Enfieldrifle with which they were equipped, although a contemporary manual warned that rifles used for that purpose were likely to be "somewhat spoilt as a precision weapon".[5]
Service
[edit]The No. 68 grenade entered service with theBritish Armyin November 1940.[1]However, it proved to be not much better than the inadequateBoys anti-tank rifleand could not be improved as the size of the explosive charge was limited by the diameter of the discharger cup,[6]It was introduced into service with theHome Guardin February 1941 and was retained until the force stood-down in 1944.[7]
A British manual of 1942, reflecting experience gained in the field, stated that the effective range of the grenade was 50 to 70 yards (45 to 65 metres) and would be best employed against the rear armour of enemy tanks after they had been allowed to pass.[8]
Notes
[edit]References
[edit]- ^abWalters, William (December 2008)."A Brief History of Shaped Charges"(PDF).Army Research Laboratory, Aberdeen Proving Ground, MD.Archived(PDF)from the original on 24 November 2020.Retrieved2 August2020.
- ^R F Eather, BSc & N Griffithe, OBE MSc -Some Historical Aspects of the Development of Shaped Charges- Ministry of Defence, Royal Armament Research and Development Establishment - 1984 - page 6 - AD-A144 098
- ^Hogg, Ian V. (1977)The Encyclopedia of Infantry Weapons of World War II,Arms & Armour Press.ISBN0-85368-281-X
- ^Clarke 2011, p. 193
- ^Clarke, Dale M (19 September 2011)."Arming the British Home Guard, 1940-1944 (pp. 177-179)".cranfield.ac.uk.Cranfield University.hdl:1826/6164.Retrieved7 August2020.
- ^Postan, Michael Moissey;Hay, Denys;Scott, John Dick (1964).Design and Development of Weapons: Studies in Government and Industrial Organisation.London: H.M. Stationery Office. p. 268.
- ^Clarke, Dale (2016).Britain's Final Defence: Arming the Home Guard 1940-1944.Stroud, Gloucestershire: The History Press. p. 66.ISBN978-0750967310.
- ^Bull, Stephen (2005).World War II Infantry Tactics: Company and Battalion.Osprey Publishing. p. 31.ISBN978-1841766638.
External links
[edit]- The Home Guard Pocket Manual, by Capt. A. Southworth, M.B.E.,p49-50: description of the No. 68 AT Grenade, use and diagram.