The story behind the development of original high-velocity small arms cartridges begins in Germany in the 1930s. The head of the company for the production of hunting rifles and carbines "Halger" was a well-known designer in Europe, Harold Gerlich. The main direction of work of Gerlich himself was the creation of a new rifle cartridge with the highest possible bullet speed. In the spring of 1930, Harold Gerlich announced that when firing from a rifle of his own design, caliber 7 millimeters, he received an initial bullet velocity of 1400 m / s and was confident in the possibility of increasing speeds above 1650 m / s. This information caused a heated controversy in the firearms press, and many prominent experts were rather skeptical of Gerlich's statement ...
In March 1931, Gerlich tested a rifle and 7 mm cartridges at the Wannsee test site, which gave a 6.5 gram bullet an initial speed of 1475 m / s. In June of the same year, such a bullet reached a speed of 1600 m / s, and when using an increased charge - an unthinkable speed of 1700 m / s. These facts refuted the doubts of the then opponents of the designer.
In his published materials, Gerlich stubbornly retained his know-how, keeping silent about the design of his bullet and the design of the rifle barrel. However, later it turned out that Gerlich's "super-high-speed" bullet was a modified and improved bullet of the Karl Puff system, which was tested back in 1907-1908. Puff's bullet had a diameter equal to the diameter of the barrel along the rifling fields; a special belt served as the leading part. The barrel rifling was also unusual - progressive rifling was used here: they were deep in the breech, and smaller in the muzzle. The bullet belt filled the rifling and flattened as it passed through the bore; due to this, the bullet met unrelenting resistance during the passage of the barrel. In addition, a pallet of compressed gunpowder was put on the back of the bullet; entering the rifling, this powder ring broke, the resulting fragments of gunpowder burned more slowly than the main charge, which led to a lower maximum pressure in the barrel, and this contributed to an increase in bullet speed. Before the shot, the powder pan played the role of an additional device for the correct location of the bullet in the sleeve, and when fired, it centered the bullet entering the barrel rifling.
Puff's bullet had a caliber of the leading part of 7.78 mm (along the girdle - 9.22 mm), a mass of 12.7 g, and a transverse load of 27.7 g / cm2. The initial speed of this bullet reached 902 m / s. However, at that time, the Karl Puff design was not used in either combat or hunting firearms. Harold Gerlich 20 years later successfully developed the Puff system by adding another leading belt to the pool, while both belts were made "significantly increased in diameter."
Gerlich's developments, perhaps, would have remained the property of a narrow circle of ballistics specialists, but during the tests, the enormous penetrating effect of the bullet unexpectedly emerged. When firing an ordinary bullet with a lead core weighing 6.5 g and an initial speed of 1450-1475 m / s. according to thick steel armor, it turned out that such a bullet makes a funnel in the armor with a depth of 15 mm and a diameter of 25 mm. An ordinary combat bullet left only scratches on the same armor. When firing at an armor plate 12 mm thick from a distance of 50 meters, a Gerlich bullet broke through a hole with a diameter of 15 mm. Further studies have shown that with a bullet speed of over 1150 m / s. in the armor, not holes of the usual type are obtained, but breaks. In this case, the armor plate at the point of impact of the bullet becomes fragile, like glass. That is, a high initial speed made it possible to reach the temporal yield strength of steel, which led to the “breaking through” of the latter. Thus, a new mechanism for breaking through steel barriers was actually discovered, in which the determining factor was not the energy of the projectile and its design features, but precisely the high initial speed.
The accuracy of the Gerlich system also significantly exceeded conventional army rifles: at a distance of 100 meters, 5 bullets weighing 6.5 g fit into a circle with a diameter of 1.7 cm, and when firing at 1000 meters, 5 bullets weighing 11.7 g fell into a circle with a diameter of 26.6 cm.
In addition, due to the high speed of the bullet, external influences on it (wind, humidity, air temperature) had very little effect on its accuracy. The shape of the trajectory was flat, so fewer rearrangements of the sight were required when firing.
The developments of Harold Gerlich had two main "highlights" - a tapered barrel and the so-called bullet weight coefficient, which changes as the bullet moves along the barrel. The tapered barrel, smoothly tapering towards the muzzle, not only gives the bullet the maximum possible speed, but also allows you to maintain this speed on the flight path. The fact is that for an ordinary bullet fired from an ordinary barrel, the weight coefficient remains unchanged. Naturally, in order to increase the speed of a bullet, you can simply reduce its weight - but then such a bullet will be unstable on its flight path. The Gerlich design bullet was an attempt to combine high initial velocity and stability on the trajectory, because due to the compression of the bullet in the barrel, the weight coefficient increased almost twice, which means that on the trajectory it kept the speed it received almost as well as and heavy bullet.
But this development also had significant disadvantages, which led to the oblivion of this type of firearm. So one of the most significant drawbacks of such firearms was the high cost of production of conical barrels. The fact is that at the beginning of the 20th century, the barrels of rifled firearms were made by drilling. Naturally, it was quite laborious to make such a “non-formatted” barrel. The second drawback was identified during the tests. And the thing was as follows - after the 400th shot, the bolt began to open with effort, and after the 500th, it completely stopped opening by hand and was opened by hitting the handle with a wooden hammer. According to his study, sagging and hardening of metal on the locking parts were found. That is, the locking elements were actually riveted by excessive recoil. And this is in almost the most powerful rifle locking mechanism of the time. These breakdowns were fixed in the workshop, after which the shooting was continued. However, after an additional 400 shots, the bolt stopped functioning again. Attempts to open it led to the fact that the bolt handle broke off. In addition, the left locking stop of the combat larva failed, one ejector broke, the second crumbled. When firing, the capsules of some cartridges, unable to withstand the pressure, fell out of the shells, leading to a breakthrough of powder gases back. Thus, the rifle withstood only 900 shots, and without repair, it functioned half as much. This meant that such firearms were simply unsuitable for military use.
Despite the obvious design flaws, ultra-high-speed ammunition required further testing, since, of course, they had the prospect of further development. However, the German authorities did not support Gerlich's research, so he moved to the UK, where he worked on the creation of an ultra-high-speed gun, and then to the USA. Where, at the Aberdeen Proving Ground in 1932-1933, the ultra-high-speed Halger-Ultra rifle of 6.197 mm caliber was tested. The initial velocity of the bullet of this system was 1760 m / s. Gerlich considered it possible to increase the muzzle velocity of a rifle bullet to 2000 m/s. After Gerlich came from America to Denmark. Moreover, the Danish government has taken appropriate measures to ensure its safety. Upon returning from Denmark to the United States in 1934, Harold died suddenly right in the train car, which at that time was passing through French territory. On the eve of the coming world such a specialist was dangerous in the camp any enemy. This leads many historians to believe that Harold Gerlich was simply "removed". Subsequently, Gerlich's ideas were safely forgotten and were implemented in only a few aircraft guns for jet aircraft. In small arms, the idea actually “died”.