152 or 155?

The War in Ukraine (2014-2023)

The ongoing war in Ukraine has increased awareness of the fact that NATO-standard 155mm projectiles cannot be fired from artillery pieces built to use Soviet-style shells with a caliber of 152mm. Few, if any, of the stories that make mention of this matter, explain the reason for this crucial difference, with stems from decisions made over a century ago.

During the last few decades of the Russian Empire, gunners in the service of the Tsar measured calibers in inches. In particular, they employed 3-inch light field guns, 4.2-inch light field howitzers, 4.7-inch heavy field guns, and 6-inch heavy field howitzers. However, as the German and French gun-founders who made many of these weapons had already adopted the metric system, these pieces were often described as 76.2mm guns, 122mm howitzers, 106.7mm guns, and 152mm howitzers.

When the Bolsheviks seized power in Russia, they imposed the metric system on the country. As this proved easier to do in the realm of language than on the shop floor of arms factories, the Red Army ended up with a lot of ordnance with metric designations that differed slightly from those in common use around the world. Ironically, many of these odd designations also applied to weapons and ammunition used by the armed forces of the British Empire, the U.S. Navy, and the Coast Artillery of the U.S. Army.

The adoption of French weapons by the American Expeditionary Force preserved the Field Artillery of the U.S. Army and Marine Corps from this fate. Indeed, for much of the twentieth century, the only first-line American field pieces with “inch” in their names were 8-inch (203mm) howitzers, the first of which was a British weapon adopted by both the French and American armies during World War I. Strange to say, rather than referring to this weapon as the obusier de 203mm (“203mm howitzer”), French gunners called it the obusier de 8 pouces.

This drawing, from the official US Army Handbook of Artillery of 1920, depicts one of the 8-inch howitzers designed by the British firm of Vickers and Company.