The Xiaolong self-propelled mortar is also a powerful infantry support weapon. Due to the development of medium-caliber and large-caliber mortars, it can already play the function of part of the howitzer. In addition, the mortar has a simple structure and is easy to carry, and the development of small and medium-caliber mortars is extremely rapid. However, the mobility of medium-caliber mortars can no longer be carried by people on their shoulders, and they need to be towed or carried on vehicles. As a result, a batch of vehicle-mounted medium-caliber self-propelled mortars came into being. With a caliber of 120 mm as the mainstream. From the perspective of structural types, there are tracked, wheeled, turret, rear-open, etc. But the Xiaolong self-propelled mortar, with a double-barreled 120-mm mortar and rear-loading interior ammunition. The biggest feature of these two self-propelled mortars is that they use a double-barreled 120-mm mortar, which can fire 6 rounds in 15 seconds, with a maximum range of 10 kilometers, and the firepower is quite powerful.

Of course, all countries are developing heavy mortars, but among the existing self-propelled mortars, the Xiaolong self-propelled mortar is superior in performance and much stronger than the self-propelled mortars of other countries. The first is its advanced chassis, and the second is a double-barreled design with a fast launch speed.

As soon as Hitler came to power in 1934, he actively expanded his armaments and prepared for launching a war of aggression. In order to be able to capture fortifications such as the Maginot Line, Hitler favored some heavy weapons, and heavy mortars were one of the secret weapons.

In the history of World War II, Germany has produced many super cannons. The most famous of these is the 600-mm mortar. In order to deal with the "Maginot Line" built by France, the German company Rheinmetall has been involved in the development of a new mortar since 1935, and in March of the following year submitted a feasibility proposal. The most exaggerated part of the scenario was that the 800-mm gun fired shells weighing 4 tons. Such heavy shells, of course, were rejected by the military, which demanded that the heavy mortar gun have a maximum range of 3 kilometers, that the artillery should enter the position for less than 6 hours, and that it should be mounted on a self-propelled chassis.

Although these demands meant that Rheinmetall had to completely change the previous concept, German designers with a natural interest in complex mechanics were enthusiastic. In August 1937, the "Plan No. 4" was introduced. The caliber of the gun was reduced to 600 mm, the shell weighed 2 tons, the charge was 350 kg, the muzzle velocity was 243 m / s, the maximum firing range was 4 km, and the high and low firing range was -10 ° ~ 75 °. The standard firing angle is 55°~75°, and the crawler font chassis is adopted. The mortar shell is front-loaded, and the cane must be lowered before shooting, and the whole preparation time for shooting is 1.5 hours. In August 1938, the military approved the improved fourth design and decided to start with one trial and six production cars. Due to the efforts of General Karl Beck of the German artillery to facilitate this during the development process, the project was named "Karl Equipment". The built 600-mm self-propelled mortar was also called the "Karl" self-propelled mortar. The project number developed is 040 device.

The chassis is a controversial part. The designers insisted that it would be more convenient to disassemble the gun into several parts and transport it. However, the assembly time was more than 6 hours, so in the end the gun was equipped with a tracked self-propelled chassis.

According to the Rheinmetall report, cars No. 1 and No. 2 were completed in November 1940, and cars No. 3~6 were completed in February~August 1941, respectively. These vehicles have been tested with 6~10 shell firing. "Karl" 600 was produced in 6 units. In March 1942, the German military proposed to develop an improved self-propelled pursuit gun, codenamed the 04L device, also known as the "Thor device". The "Thor device" was distinguished by the reduction of the caliber of the gun to 540 mm. But the firing range is longer, and the "Thor device" 540 is also collectively known as the "Changer" 540 mm self-propelled pursuit gun. Production quantity: 5~6 vehicles.

Despite its short barrel, the 600mm mortar was still a behemoth, with a total combat weight of 124 tons, which was as heavy as two heavy tanks. The number of the artillery squad was 19 people, including 1 commander. The length of the vehicle is 11.37 meters, and the width of the vehicle is 3.16 meters. The height of the vehicle is 4.78 meters. The short, thick barrel is its main external feature.

Undoubtedly, artillery and shells are the most important components and power of the "Karl" 600 self-propelled mortar. The 040 unit is a 600 mm pursuit gun (mortar gun) with a barrel length of 8.44 times. is 5.064 meters, the projectile is rear-loaded. Unit 041 has a 540 mm gun, but its barrel is 11.5 times longer and 6.21 meters. That is, although the latter has a slightly smaller caliber, its range is also longer than the former due to the lengthened body barrel. The high and low firing range of 600 mm pursuit guns is 0~70 degrees, and they usually shoot in the range of 55-70 degrees. The firing range in the direction of the artillery was only 4 degrees to the left and right. In other words, beyond this range, aiming can only be achieved by turning the hull. The weight of the gun itself was more than 60 tons, and it is incredible that the pitching of the gun was achieved manually. However, consider Archimedes' famous saying: "Give me a lever long enough and I can pry the earth", then, as long as there are enough gear ratios, it is also achievable to pitch the gun. In this way, it will take at least 4~6 minutes to raise the gun to the maximum elevation angle. Its stated rate of fire is 6 rounds / hour, that is, 1 shell is fired every 10 minutes. In addition to the difficulty of shaking the cannon, it is also quite laborious to load the shells, and it is necessary to use a crane to lift the 2-ton shell head into the slot at the tail of the gun, and then use a special ejector rod to push the bullet into the chamber, and then push the ****** into the chamber.

Due to the huge caliber, the size and weight of its shells are also very remarkable. The original projectile used for the 600 mm gun was a concrete penetration projectile with a warhead 2.51 meters long, a weight of 2.17 tons, and a 270 kilogram of explosives. With the 1 charge, the firing range is 2840 meters; With a 4 charge, the muzzle velocity is 220 m / s, and the firing range is up to 4320 m. In 1942, in order to increase the firing range, a light concrete penetration bomb was developed, with a warhead weighing 1,700 kilograms, containing 220 kilograms of explosives, and a maximum range of 6,640 meters when using 9 charges. When a 600 mm concrete penetrating projectile is fired, it can penetrate a 2.5-meter-thick reinforced concrete fortification and then explode.

However, any design that goes to the extreme is doomed to fail. Although the 600mm self-propelled mortar is powerful, it is too large, the protection is too poor, and most importantly, the ammunition carrying capacity is said to be only 2 rounds. So its role is really too limited, far inferior to a medium-caliber mortar like the Xiaolong self-propelled mortar. (To be continued.) )