Intermediate cartridge

An intermediate cartridge is a rifle/carbine cartridge that has a reduced range and power in comparison to fully powered cartridges (such as the .303 British, 7.62×54mmR, 7.92×57mm Mauser, 7.7×58mm Arisaka, .30-06 Springfield or 7.62×51mm NATO), but still has greater length than pistol/personal defense weapon cartridges.[1] As their recoil is significantly reduced compared to full-power rifle cartridges, fully automatic rifles firing intermediate cartridges are relatively easy to control. However, even though less powerful than a traditional full-power rifle cartridge, the ballistics are still sufficient for an effective range of 300–600 metres (330–660 yd), which are the maximum typical engagement ranges in modern combat. This allowed for the development of the assault rifle, a selective fire weapon that is more compact and lighter than rifles that fire full-power rifle cartridges.

Service rifle cartridge cases: (Left to right)
Full power cartridges:
7.62×54mmR
7.62×51mm NATO
Intermediate cartridges:
7.62×39mm
5.56×45mm NATO
5.45×39mm.
The Sturmgewehr 44, a development of the earlier Maschinenkarabiner 42(H)

The first intermediate cartridge to see widespread service was the German 7.92×33mm Kurz used in the StG 44.[1] Other examples include the Soviet 7.62×39mm M43 (used in the SKS and AK47), 5.45×39mm M74 (used in the AK-74, which replaced the AK47), the Chinese 5.8×42mm (used in the QBZ-95) and the American 5.56×45mm NATO (used in the M16 and M4)

History

The late 19th and early 20th century saw the introduction of smokeless powder cartridges with small caliber jacketed spitzer bullets that extended the effective range of fire beyond the limitations of the open rifle sight lines. The Maxim gun, the world's first machine gun, was devised in 1885, and a year later, the Lebel Model 1886 rifle, had the distinction of being the world's first smokeless powder bolt-action rifle. In the years leading up to World War I, the Lebel set an international example, and smokeless powder rifles began to be produced by all the world's great powers. This included, but was not limited to, the German Gewehr 98, the British Lee–Enfield, the Russian Mosin–Nagant, and the American M1903 Springfield. These rifles weighed over 8 lb (3.6 kg), and they were longer than 40 in (1,000 mm) and as such were generally inappropriate for close combat. They fired cartridges capable out to over 1,000 m (1,100 yd) but typical combat ranges were much shorter, around 100–300 metres (110–330 yd), rarely exceeding 500 metres (550 yd).[2]


Therefore, the potential of the full-power rifle ammunition at longer ranges was seldom needed.

...if hasty wartime training was such that he [the infantryman] had no better than a fifty percent chance of hitting a target at 300 yards (270 m), there was no logical reason to give him a rifle and ammunition designed to kill at 2,000 yards (1,800 m)

— Ian V. Hogg, Modern Small Arms[3]

During World War II, to improve close combat ability, some semi-automatic rifles were created, such as the American M1 Garand and the German Gewehr 43, but for close quarter combat, a more common sight was the submachine gun. Weapons such as the Soviet PPSh-41, US Thompson, British Sten and the German MP-40 had fully automatic fire, and were still easily controllable due to the fact they used pistol cartridges. These submachine guns could provide high rates of controllable fire, but they lacked the stopping power and longer effective range of the battle rifles.

In 1951, the US military published the M1 Garand's fire rate; a trained soldier averaged 40–50 accurate shots per minute at a range of 300 m (330 yd). "At ranges over 500 m (550 yd), a battlefield target is hard for the average rifleman to hit. Therefore, 500 m (550 yd) is considered the maximum effective range, even though the rifle is accurate at much greater ranges".[4] What was needed was a more compact, selective fire weapon, firing a cartridge combining the range and power of a rifle, with recoil nearly as low as a pistol cartridge. The resulting firearm would have the accuracy of the former (within expected typical combat ranges), but able to project the volume of fire of the latter at closer quarters.

Though technically a full powered cartridge, the first one to fulfil this requirement may have been the Japanese 6.5×50mm Arisaka used by the Russian Fedorov Avtomat rifle, used in limited numbers from 1915-1917 (the cartridge itself dates back to 1897). The Fedorov was arguably the first assault rifle.[5][6] Later came the US M1 Carbine, which used the .30 Carbine cartridge and was developed as a weapon for officers and rear area soldiers unlikely to be involved in infantry assault but who needed a weapon more effective than a pistol. Soon after came the 7.92×33mm Kurz round developed by the Germans in 1938, which was a shortened version of the standard 7.92×57mm Mauser round, and was used in the StG-44, which is more commonly considered to be the first assault rifle.[1][7][8] When the Soviets developed the AK-47, they already had an intermediate cartridge of their own, the 7.62×39mm, which was used in the SKS, a weapon which saw very limited use in the closing stages of World War II, but was quickly replaced once the AK-47 entered service.[9]

Since the 1960s the United States, NATO, the (former) Warsaw Pact, the People's Republic of China, and other countries adapted relatively small sized, light weight, high velocity military intermediate service cartridges in the form of the .223 Remington (1964), 5.56×45mm NATO (1980), Soviet 5.45×39mm (1974), and Chinese 5.8×42mm (1987). These intermediate cartridges allow a soldier to carry more ammunition for the same weight compared to their larger and heavier predecessor cartridges, have favourable maximum point-blank range or "battle zero" characteristics and produce relatively low bolt thrust and free recoil impulse, favouring light weight arms design and automatic fire accuracy.[10][11][12] [13][14]

Universal service cartridge

Some militaries have considered adoption of a 'universal service cartridge' - a replacement of small caliber, high velocity intermediate cartridges and full-power cartridges with a cartridge at the larger end of the intermediate cartridge spectrum, well suited for both assault rifle and general purpose machine gun use in the 6mm caliber to 7mm caliber caliber range, with external and terminal ballistic performance close or equal to the 7.62×51mm NATO and 7.62×54mmR full-power cartridges.[15][16] The .280 British (7×43mm) and Czech 7.62×45mm were early attempts to create universal service cartridges. The US Army conducted testing of telescoped ammunition, polymer-cased ammunition and caseless ammunition for future service cartridges.[17] The viability of a universal service cartridge has been criticised,[18] and as of 2020, no intermediate cartridge has been replaced.

Characteristics

Typical intermediate cartridges have:

  • Necked cartridge
  • According to the official C.I.P. (Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives) and NATO EPVAT rulings the maximum service pressures range between 340.00–430.00 MPa (49,313–62,366 psi) Pmax piezo pressure
  • muzzle energies ranging between 1,250–2,500 J (922–1,844 ft⋅lbf)
  • Muzzle velocities ranging between 700–950 m/s (2,297–3,117 ft/s)
  • Relatively low Oratio's ranging between 4.29 and 7.99

List of intermediate cartridges

Service cartridges

Service cartridges are cartridges the service rifles of armies were or are chambered for.

Prototype cartridges
This list is incomplete; you can help by adding missing items with reliable sources.
  • 4.85×49mm cartridge of the experimental Enfield IW assault rifle
  • 6×45mm SAW cartridge of the experimental Rodman Laboratories XM235 light machine gun, a project which terminated in the M249
  • 6.5×39mm cartridge based on the 7.62×39mm of variants of the AR-15 and Zastava M70 assault rifles
  • 6.8mm Remington SPC (6.8×43mm) cartridge of the limited service LWRC M6 assault rifle
  • .280 British (7×43mm) cartridge of the experimental and briefly serviced EM-2 assault rifle
  • 7.5×38mm chambered for the CEAM Modèle 1950 rifle and experimental French variant of StG 45(M) rifle
  • 7.65×33mm Argentine variant of German 7.92×33mm cartridge for use in Argentine copy of German Sturmgewehr 44 assault rifle
  • 7.65×35mm chambered in CEAM Modèle 1950 and experimental French variant of the StG 45(M) rifle
  • 7.75×39mm GeCo the first intermediate round ever made, German experiment
  • 12.7×55mm STs-130 subsonic cartridge of the limited service ShAK-12 assault/battle rifle

See also

References
  1. Bull, Stephen (2004). Encyclopedia of Military Technology and Innovation. Greenwood. p. 25. ISBN 978-1-57356-557-8.
  2. Military Small Arms Of The 20th Century, 7th Edition, 2000 by Ian V. Hogg & John S. Weeks, p.243
  3. Hogg, Ian V. (1983). Modern Small Arms. United Kingdom: Bison Books Ltd. p. 136. ISBN 978-1-85841-075-3.
  4. U. S. RIFLE, CALIBER .30, M1, DEPARTMENTS OF THE ARMY AND THE AIR FORCE, October 1951
  5. Williams, Anthony (6 Feb 2012). "Assault Rifles and their Ammunition: History and Prospects". Retrieved 4 Apr 2012.
  6. Болотин, Давид (1995). "Глава 5. Автомат Фёдорова и унификация стрелкового оружия на его базе" (PDF). История советского стрелкового оружия и патронов (in Russian). СПб.: Полигон. pp. 156–165. ISBN 5-85503-072-5.
  7. Williams, Anthony G. (June 22, 2008). "Assault Rifles and Their Ammunition: History and Prospects". Military Guns & Ammunition. Archived from the original (PDF) on July 14, 2008. Retrieved April 3, 2018.
  8. Hallock, Richard R. (March 16, 1970). "M16 Rifle Case Study. Prepared for the President's Blue Ribbon Defense Panel" (PDF). p. 162.
  9. "SKS Simonov -- Modern Firearms". Modernfirearms.net. Archived from the original on 2018-02-15. Retrieved 2018-02-09.
  10. Assault Rifles and Their Ammunition: History and Prospects by Anthony G. Williams
  11. "An Improved Battlesight Zero for the M4 Carbine and M16A2 Rifle". Retrieved 2007-09-11.
  12. "TM 9-1005-319-10 (2010) - Operator's Manual for Rifle, 5.56 MM, M16A2/M16A3/M4 (Battlesight Zero pages 48-55)" (PDF). Retrieved 2014-06-03.
  13. Nathaniel F (5 March 2016). "Caliber Configuration: How It Got to Where It's At, and Where It's Headed". tehfirearmblog.com. Retrieved 14 May 2017.
  14. Nathaniel F (9 April 2016). "How Much Does Your Ammo Weigh?". thefirearmblog.com. Retrieved 14 May 2017.
  15. South, Todd (7 May 2017). "New rifle, bigger bullets: Inside the Army's plan to ditch the M4 and 5.56". armytimes.com. Retrieved 14 May 2017.
  16. Nathaniel F (5 March 2016). "Caliber Configuration: How It Got to Where It's At, and Where It's Headed". thefirearmblog.com. Retrieved 14 May 2017.
  17. Trevithick, Joseph (10 May 2017). "The Army Is Once Again Looking to Replace the 5.56mm Cartridge". thedrive.com. Retrieved 15 May 2017.
  18. Wayner, Josh (6 October 2016). "Why Universal Service Cartridges Will Never Happen". thetruthaboutguns.com. Retrieved 15 May 2017.
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