What is the difference between a sub-caliber projectile and a conventional armor-piercing projectile

2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16

Immediately after the appearance of armored protection of military equipment, the designers of artillery weapons began work on creating tools capable of effectively destroying it.

An ordinary projectile was not quite suitable for this purpose, its kinetic energy was not always enough to overcome a thick barrier made of heavy-duty steel with manganese additives. The sharp tip crumpled, the body collapsed, and the effect turned out to be minimal, at best a deep dent.

Russian engineer-inventor SO Makarov developed the design of an armor-piercing projectile with a blunt front. This technical solution provided a high level of pressure on the metal surface at the initial moment of contact, while the impact site was subjected to strong heating. Both the tip itself and the area of the armor that had been hit melted. The remaining part of the projectile penetrated the resulting fistula, causing destruction.

Sergeant major Nazarov did not have theoretical knowledge of metallurgy and physics, but intuitively came to a veryinteresting design, which became the prototype of an effective class of artillery weapons. Its sub-caliber projectile differed from the usual armor-piercing one in its internal structure.

In 1912, Nazarov proposed to introduce a strong rod into ordinary ammunition, which is not inferior to armor in its hardness. The officials of the War Ministry brushed aside the annoying non-commissioned officer, considering, obviously, that an illiterate retiree could not invent anything sensible. Subsequent events clearly demonstrated the harmfulness of such arrogance.

Krupa received a patent for a sub-caliber projectile already in 1913, on the eve of the war. However, the level of development of armored vehicles at the beginning of the 20th century made it possible to do without special armor-piercing means. They were needed later, during World War II.

The principle of operation of a sub-caliber projectile is based on a simple formula known from the school physics course: the kinetic energy of a moving body is directly proportional to its mass and the square of its speed. Therefore, to ensure the greatest destructive ability, it is more important to disperse the striking object than to make it heavier.

This simple theoretical position finds its practical confirmation. A 76-mm sub-caliber projectile is twice as light as a conventional armor-piercing projectile (3.02 and 6.5 kg, respectively). But to provide striking power, it is not enough just to reduce the mass. Armor, as the song says, is strong and requires extra tricks to break through.

If a steel bar with a uniform internal structure hits a solid barrier, it will collapse. This process, in slow motion, looks like the initial collapse of the tip, an increase in the contact area, strong heating and spreading of molten metal around the impact site.

An armor-piercing sabot projectile works differently. Its steel body shatters upon impact, absorbing some of the thermal energy and protecting the heavy-duty interior from thermal destruction. The ceramic-metal core, having the shape of a somewhat elongated thread spool and a diameter three times smaller than the caliber, continues to move, punching a small-diameter hole in the armor. In this case, a large amount of heat is released, which creates a thermal distortion, which, in combination with mechanical pressure, produces a destructive effect.

The hole formed by the sub-caliber projectile has the shape of a funnel, expanding in the direction of its movement. It does not require damaging elements, explosives and a fuse, fragments of armor and core flying inside the combat vehicle pose a mortal threat to the crew, and the generated thermal energy can cause detonation of fuel and ammunition.

Despite the variety of anti-tank weapons, sabots, invented over a century ago, still have their place in the arsenal of modern armies.