First of all, let us ask ourselves the question, what is a “non-standard caliber”? After all, since there is a gun, it means that its caliber is recognized as standard! Yes, this is so, but it so happened historically that the standard in the armies of the world at the beginning of the twentieth century was considered to be a multiple of one inch. That is, 3 inches (76.2 mm), 10 inches (254 mm), 15 inches (381 mm), and so on, although, of course, there were differences here. In the same howitzer artillery of the First World War, there were "six-inch" guns of 149 mm, 150 mm, 152, 4 mm, 155 mm caliber. There were also guns of calibers 75 mm, 76 mm, 76, 2 mm 77 mm, 80 mm - and all of them were called "three-inch". Or, for example, for many countries, the standard caliber of steel is 105 mm, although this is not quite a 4-inch caliber. But it just so happened, this caliber turned out to be very popular! But there were also such guns and howitzers, the caliber of which differed from generally accepted standards. It is not always clear why this was necessary. Wasn't it possible to reduce all the guns in your army to just a few of the most commonly used calibers? This makes it easier both to produce ammunition and to supply troops with them. And it is also more convenient to sell weapons abroad. But no, as in the eighteenth century, when for different types of infantry and cavalry, different, sometimes even different-caliber guns and pistols were produced - officer, soldier, cuirassier, hussar, jaeger, and infantry, then with guns in the First World War, it was almost everything is the same!
Well, our story begins, as always, with Austria-Hungary and its weapons of the early twentieth century, actively participating in the First World War. Here, this became the 7-cm mountain gun M-99 - a typical example of outdated types of weapons, which, nevertheless, were used during the war in many countries until more advanced systems appeared. It was a gun with a bronze barrel, without any recoil devices, but rather light. A total of 300 copies were produced, and when the war broke out, about 20 batteries of mountain cannons of this type were used at the front in the Alps. The weight of the gun was 315 kg, the elevation angles were from -10 ° to + 26 °. The projectile weighed 4, 68 kg and had an initial speed of 310 meters, and the maximum firing range was 4.8 km. They replaced it with a 7, 5-cm mountain howitzer of the Skoda company M.15 and it was already quite a modern weapon for that time. In particular, its firing range reached 8 km (that is, even more than that of the 8-cm M.5 field gun!), And the rate of fire reached 20 rounds per minute!
Well, then the "Shkodovites" swung themselves so badly that they released the M.16 10-cm mountain howitzer (based on the M.14 field howitzer). The main difference was, of course, in the fact that it could be taken apart and transported in a pack way. The weight of the howitzer was 1, 235 kg, guidance angles from -8 ° to + 70 ° (!), And horizontally 5 ° in both directions. The weight of the projectile was very decent - 13.6 kg (a hybrid shrapnel-grenade projectile from the M.14), an initial speed of 397 m / s, and a maximum reach of 8.1 km. They also used a 10 kg high-explosive shell and 13.5 kg shrapnel from the M.14. The rate of fire reached 5 rounds per minute, the crew was 6 people. In total, 550 of them were produced, and they actively participated in the battles with the Italians. After World War I, it was in service with the armies of Austria, Hungary and Czechoslovakia (under the designation 10 cm howitzer vz. 14), was exported to Poland, Greece and Yugoslavia, and was used as a captured weapon in the Wehrmacht.
It would seem that one could be satisfied with this 3, 9-inch caliber, but no, exactly 4-inch caliber was needed, as if the addition of 4 mm could seriously change something in the merits of the gun. As a result, Skoda developed the 10.4cm M.15 cannon, which is similar in design to the German 10 cm K14 cannon. A total of 577 M.15s were produced and they were used in both Europe and Palestine. The design is typical for Skoda - a hydraulic recoil brake and a spring-loaded knurler. Barrel length was L / 36.4; the weight of the gun is 3020 kg, the vertical guidance angles are from -10 ° to + 30 °, the horizontal guidance is 6 °, and the firing range is 13 km. The weight of the projectile to the gun was 17.4 kg, and the number of the crew was 10 people. Interestingly, 260 M.15 guns were inherited by Italy in 1938-1939. were bored to the traditional 105 mm and served in the Italian army under the designation Cannone da 105/32. In addition to the caliber, the Italians replaced wooden wheels with pneumatics for them, and from which the towing speed of these guns increased significantly.
As for the proud British, they had a whole bunch of non-standard caliber guns, and they all fought in the First World War. Let's start again with the 10 Pounder Mountain Gun. The fact that it was called a 10-pounder means little, the caliber is important, but it was equal to 2.75 inches or 69.8-mm, that is, the same 70 as the Austrian mining gun. When fired, the cannon rolled back and, moreover, fired black powder, but very quickly it was disassembled into parts, the heaviest of which weighed 93, 9 kg. The weight of the shrapnel projectile was 4.54 kg, and the range was 5486 m. The barrel unscrewed into two parts, which was of fundamental importance for such a weapon. But it was precisely a cannon, so it could not fire at high-lying targets!
The gun was used in the Anglo-Boer War of 1899-1902, where its crews suffered losses from the fire of the Boer riflemen, and in the First World War, the British used it in the Gallipoli Peninsula, as well as in East Africa and Palestine. However, it was obvious that this gun was already outdated and in 1911 it was replaced with a new model: a 2, 75-inch mountain cannon of the same caliber, but with a shield and recoil devices. The weight of the projectile increased to 5, 67 kg, as well as the weight of the gun itself - 586 kg. To transport it in packs, 6 mules were required, but on the other hand, it was assembled in position in just 2 minutes, and dismantled in 3! But the gun retained the disadvantage of its predecessor - separate loading. Because of what its rate of fire was less possible. But the range remained at the same level, and the power of the projectile even increased slightly. They used it on the Mesopotamian front and near Thessaloniki. But they were made a little, only 183 guns.
And then it got even more interesting. A 3, 7-inch mountain howitzer entered service, that is, a 94-mm cannon. It was tested in action for the first time in March 1917, and already in 1918, 70 such guns were sent to Mesopotamia and Africa. It was the first British gun to have horizontal guidance equal to 20 ° to the left and right of the barrel axis. The inclination and elevation angles of the trunk were -5 ° and + 40 °, respectively. The loading was also separate, but for the howitzer it was an advantage, not a disadvantage, since it gave a whole bunch of trajectories when firing. The new gun could fire 9, 08 kg with a projectile at a distance of 5, 4km. The barrel was split into two parts, 96 kg and 98 kg each, and the total weight of the system was 779 kg. On the road, the gun could be towed by a couple of horses, and it remained in service with the British army until the early 1960s!
But, further, as they say - more! Already in 1906, the British military wished to have a more advanced 5-inch howitzer than the previous one, but not a 105-mm gun, like the Germans, but adopted a completely new caliber proposed by Vickers - 114 mm or 4.5 inch. It is believed that in 1914 it was the most perfect weapon in its class. Weighing 1, 368 kg, she fired high-explosive shells weighing 15, 9 kg at a distance of 7.5 km. The elevation angle was 45 °, the horizontal aiming angle was "miserable" 3 °, but the other howitzers had only a little more. The shells were also used for smoke, lighting, gas, and shrapnel. Rate of fire - 5-6 rounds per minute. Rollback brake - hydraulic, spring reel. Until the end of the war, more than 3,000 of these howitzers were manufactured, and they were delivered to Canada, Australia, New Zealand, and in 1916, 400 copies were sent to us in Russia. They fought in Gallipoli, the Balkans, Palestine and Mesopotamia. After the war, they changed their wheels and in this form they fought in France and were abandoned near Dunkirk, and then as training in Britain itself, they were in service until the end of the war. They were part of the Finnish army in the "Winter War". Moreover, it was they who were used to equip the VT-42 self-propelled guns based on our captured BT-7 tanks. As part of the Red Army, they also fought back in 1941. In addition, British artillery boats were equipped with a gun of the same caliber, but, in general, it was never used anywhere else! Several years ago, one such howitzer stood on the second floor of the historical museum in Kazan, but whether it is there now, I personally do not know.
There is a saying: with whom you lead, from that you will gain. So Russia was led to an alliance with Britain, and from her it got both a 114-mm howitzer and … a 127-mm cannon! As you know, 127-mm is a "sea caliber", the classic 5 inches, but on land it was used only in England! Well, we also have in Russia, Britain's ally during the First World War. In England, this gun was called the BL 60-Pounder Mark I, was adopted in 1909 to replace the old gun of this caliber, which did not have recoil devices. The 127-mm cannon could fire 27.3 kg shells (shrapnel or high-explosive grenade) at a distance of 9.4 km. In total, 1773 guns of this type were produced during the war years.
We improved it gradually. First, they gave a new, aerodynamic shape to the projectiles and the firing range increased to 11, 2 km. Then, in 1916, the barrel was lengthened on the Mk II modification, and it began to shoot up to 14.1 km. But the gun turned out to be heavy: the combat weight was 4.47 tons. In the British army, this gun was used until 1944. In the Red Army in 1936, there were only 18 of them, but, nevertheless, they were in service until 1942.
