12.7x81mmSR explained
| 12.7×81mm |
| Origin: | UK |
| Type: | Heavy Machine Gun |
| Design Date: | 1923 |
| Parent: | Vickers .5V/580 |
| Case Type: | Semi-rimmed, bottlenecked |
| Bullet: | 13.05mm |
| Neck: | 13.8mm |
| Base: | 18.32mm |
| Rim Dia: | 19.55mm |
| Case Length: | 81.2mm |
| Length: | 107.2mm |
| Primer: | Berdan |
| Bwunit: | gram |
| Bw1: | 36.6 |
| Vel1: | 760 |
The 12.7×81mmSR cartridge was created by Vickers as an export variant of the cartridge developed for the Vickers .50 machine gun. The major changes were to modify the case from rimless to Semi-Rimmed and reduce the bullet weight from 580gr to 565gr.[1]
History
Vickers sold a number of weapons chambered in the cartridge to Italy and Japan, who developed their own weapons that utilized that cartridge.[2]
The cartridge was adopted by Italy in 1933 with the Breda-SAFAT and Scotti–Isotta Fraschini Modello 1933 machine guns, which armed most of the aircraft of the Regia Aeronautica from the Ethiopian War to the Second World War. The cartridge remained in production until the 1970s, when the last Breda-SAFAT machine guns, that were in service until the 1970s as reserve weapons of the Italian Air Force, were decommissioned.
As aircraft of the Corpo Truppe Volontarie and the Fiat CR.32 fighters supplied to the Nationalists during the Spanish Civil War were armed with the Breda-SAFAT, the cartridge was produced in Spain by "Pirotécnica" of Seville.
Hungary also produced the Reggiane Re.2000 under license which was armed with the Gebauer 1940.M GKM machine gun, which used the cartridge.
In 1941 Type 1 machine gun variants (Ho-103 in fixed mounts and Ho-104 in flexible mounts) were introduced by Japan as aircraft-mounted heavy machine guns using the cartridge.
Alternate names
[3]
- 12.7mm Breda
- 12.7 x 81 SR
- 12.7mm Type 1
- 12.7mm Mod. 36
- 12.7mm Japanese
- .5 in. V/565 Vickers-Armstrong
Cartridge variants
[4] [5] [6]
- Ball (full metal jacket), marked with a pink or red seal around the casemouth.
- Armor piercing (AP) of Italian origin, marked with a black tip.
- Armour piercing tracer (AP-T) with red tracer, marked with a pink tip and green and white seal around the casemouth.
- AP-T with brighter-burning, longer-lasting red tracer, uncolored tip and black seal around the casemouth.
- AP-T with white tracer, uncolored tip and green and white seal around the casemouth.
- Fuzed high-explosive incendiary (HEI) of Italian origin, its body painted blue or red. Contained 0.8g of PETN and incendiary composition.
- Ma 103 fuzed HEI, marked with a white seal around the casemouth. Contained 0.8g of RDX and 1.46g incendiary composition.
- Ma 102 fuzeless HEI, marked with a dark purple seal around the casemouth. Contained 2g of PETN + RDX and 1.46g incendiary composition.
See also
Notes and References
- Web site: .5 Vickers Mk I Rimless . 2024-09-29 . Municion Org . en.
- Web site: THE .5" VICKERS GUNS AND AMMUNITION . 2024-09-29 . Wayback Machine . en.
- Web site: 12.7 x 81 SR (v/565) - The Vickers Machine Gun. 2024-09-29 . The Vickers Machine Gun . en.
- Book: Japanese Explosive Ordinance (Army Ammunition Navy Ammunition) . Chapter 4 . 2 . 1 . Washington, D.C, USA . United States Government Printing Office . 16 Mar 1953 . 279 . TM 9-1985-5/TO 39B-1A-12 .
- Book: Japanese Ammunition - C.I.AMN. Technical Report . 24 . 2 . Khadki, India . Chief Inspector of Ammunition, Kirkee . 1945 . 3–4 .
- Japanese Ammunition 1880-1945 vol. 1, Ken Elks,
