155 mm caliber

"155 mm" is a very widely used calibre (barrel internal diameter) for artillery guns and their corresponding artillery shells.

Land warfare

Historic calibres

France - 1874

The 155 mm (6.1 in) caliber originated in France after the Franco-Prussian War (1870–1871).

A French artillery committee met on 2 February 1874 to discuss new models for French fortress and siege artillery, among which there was a weapon in the 140 to 160 mm (5.5 to 6.3 in) calibre range.

After several meetings, on 16 April 1874 the committee settled on the 155 mm (6.1 in) calibre, and led to the De Bange 155 mm cannon.

NATO standard

Among the existing and the former 155 mm artillery shells, there is one that has been standardised by NATO under both the AOP-29 part 1 (in reference to STANAG 4425), and under the JBMoU[de] (Joint Ballistics Memorandum of Understanding). This standard defines a standard 155 mm projectile with a 23 litre combustion chamber volume.

NATO is now pushing from standardised artillery shell to sharable ammunition. The standard described above enables the use of NATO shells in all NATO guns. But they still need to be qualified on each gun to control the performances (ballistic characteristics) and safety.

Retirement of other calibres

This has led to the obsolescence of larger caliber artillery shells such as the 175 and 203 mm (6.9 and 8.0 in). Some militaries continue to retain the smaller 105 mm (4.1 in) weapons for their light weight and greater portability. Russia and former Eastern Bloc countries tend to use 122, 130, and 152 mm (4.8, 5.1, and 6.0 in) artillery in similar roles.

Naval warfare

Since the end of World War II, the 155 mm (6.1 in) caliber has not found any use among naval forces despite its ubiquity on land with most NATO and aligned navies using 76 mm (3.0 in), 100 mm (3.9 in), 114 mm (4.5 in), or 127 mm (5.0 in) guns on modern warships. At one point the British Ministry of Defence studied "up-gunning" the Royal Navy's 4.5 inch Mark 8 naval guns to give increased firepower and a common caliber between the Royal Navy and the British Army. Despite superficially appearing to be inferior based on a simple comparison of round diameters, when firing conventional ammunition the smaller, 4.5 inch Mark 8 naval gun is comparable to the standard 155 mm (6.1 in) gun-howitzer of the British Army. The standard shell from a 4.5 inch Mark 8 naval gun has the same, if not better, range. Only by using rocket-assisted projectiles (RAPs) can most 155 mm (6.1 in) guns have comparable range to the 4.5 inch Mark 8 naval gun and by doing so there is a reduction in the payload. This is because naval guns can be built much more strongly than land-based self-propelled gun-howitzers, and have much longer barrels in relation to caliber (for example the 4.5 inch Mark 8 naval gun has a barrel length of 55 calibers, while the standard AS-90 self-propelled gun has a barrel length of 39 calibers). This allows naval guns to fire heavier shells in comparison to shell diameter and to use larger propellant charges in relation to shell weight, leading to greater projectile velocities. Even without active cooling, the heavier naval gun barrels allow a faster sustained rate of fire than field guns, and this is exploited with an autoloading system with a capacity of several hundred rounds. The 155 mm (6.1 in) is better than the 4.5 inch Mark 8 naval gun for firing cannon-launched guided projectiles (CLGP) as the lower velocity of the 155 mm (6.1 in) shell makes it much easier for the projectiles' internal electronic guidance systems to survive being fired.

While the US Navy's Advanced Gun System (AGS) also uses a 155 mm (6.1 in) caliber, it is not compatible with NATO-standard 155 mm (6.1 in) ammunition. Only one type of ammunition was ever developed and procurement was discontinued in 2016 due to its high cost, making the AGS unusable.

155 mm guns

Current

NATO and allies

• Finland 155 K 83 155 GH 52 APU
• France CAESAR GCT
• Germany Artillery Gun Module PzH 2000
• Germany / United Kingdom / Italy FH70
• Israel SIGMA 155 ATMOS 2000 Soltam M-71
• Italy Palmaria
• Japan Type 99 Type 19
• Poland AHS Krab
• South Korea K9 Thunder KH179
• Singapore FH-2000 SLWH Pegasus SSPH Primus
• Slovakia 155 mm SpGH Zuzana
• Spain Santa Bárbara Sistemas 155/52
• Sweden Archer artillery system FH77
• Turkey Panter howitzer
• Turkey / South Korea T-155 Fırtına
• Ukraine 2S22 Bohdana 2P22 Bohdana
• United Kingdom AS-90
• United Kingdom / United States M777
• United States M109 howitzer M114 howitzer M198 howitzer

Other countries

Compatible with NATO projectiles:

• India Dhanush ATAGS Bharat-52
• Russia 2S19M1-155 – the 155 mm export version
• Serbia Nora B-52

Unknown compatibility:

• China WAC-21 PLZ-45 PLZ-05 PCL-181
• South Africa G5 G6

Historic

• France GPF 155 mm St. Chamond 155 mm Schneider 155 mm Obusier de 155 mm Modèle 50 TRF1
• Israel Soltam M-68
• Japan Type 75
• Serbia Nora B-52
• Singapore FH-88
• Sweden Bandkanon 1
• United States M1/M2 155 mm "Long Tom" M12 M41 M44 M53

Experimental or prototype-only

• United States XM1203 (five prototypes built) XM2001 (one prototype built). Both never entered service M1299 (20 prototypes built)
• Poland AHS Kryl – one prototype built, never entered service

155 mm naval guns

NATO compatible

• Germany: Modular Naval Artillery Concept (MONARC) – proposed but never produced
• United Kingdom: 155 mm (6.1") Future Naval Gun – proposed but never produced

Not NATO compatible

• Empire of Japan: 15.5 cm/60 3rd Year Type naval gun
• France: Canon de 155 mm Modèle 1920
• United States: Advanced Gun System (AGS) – in limited service, but with no ammunition available

155 mm shells

Twenty-first century production and usage rates

As of February 2023[update]–March 2023, Ukraine was firing up to 10,000 artillery shells per day, with the average monthly rate of 90,000–110,000 of 155 mm shells. In March 2023, the Ukrainian defense minister asked allies for 250,000 of such shells per month.

Before the start of the large-scale Russian invasion of Ukraine (2022), the US produced 14,400 shells per month. As of March 2023[update], the rate has increased to 20,000 per month. The US declared its plans to increase the production to 90,000 per month, to reach 1,000,000 shells per year in 2025.

Germany's Rheinmetall was producing 60,000–70,000 per year in 2022. Rheinmetall said it was ready to boost production to 500,000 per year.

Ukraine has a domestic production of shells. As of December 2022, the production rate was "in the thousands".

In summer 2023, the EU approved a plan that provides for the production of 650,000 large-calibre ammunition per year, and pledged to supply one million artillery shells to Ukraine over the next 12 months.

External links

• Media related to 155mm artillery ammunition NATO at Wikimedia Commons