projectile

A projectile , also known colloquially as a bullet , is a projectile fired from a firearm .

etymology

The term projectile is a derivative of the French "projectile" and is mainly used for projectiles from handguns .

Basics

The terms projectile and projectile are used almost synonymously in the literature on weapons technology, whereby projectile is understood as a sub-term of projectile. The general principles described in the article bullet apply to projectiles:

Projectile types

Half of a bronze hollow mold for casting muzzle-loading projectiles with a diameter of 13 mm and a height of 28 mm
Projectiles 9 mm P8 or Uzi / MP2, 7.62 mm G3 or MG3 - the traces of the barrel are clearly visible

material

In the early days of firearms, stone bullets were used first , then iron and lead . Today's projectiles are made of steel , lead, copper and can contain depleted uranium or tungsten . Other projectiles do not derive their effectiveness from the kinetic energy, but from their explosive filling. An example of this are rifle grenades (projectiles filled with explosives).

shape

At first, projectiles were fired in a spherical shape (e.g. the classic cannonball ), which is why projectiles are colloquially referred to as bullets to this day.

A modern projectile is usually designed as a long projectile, i.e. has a cylindrical shape with a mostly pointed front part and a slightly tapering end. It is given a twist in the course to stabilize it in flight.

Depending on the shape of the tip, the projectile is as sharp , semi-pointed or round called, also still exist some special types: hollow-point bullet have a concave top, which on impact to a greater deformation (mushrooming) and thus stronger effect on the target leads. For this reason, they are often confused or equated with semi-jacketed bullets . Flat head bullets are bullets with a flattened head. They are particularly needed for weapons with tubular magazines to prevent the tip of a cartridge from exerting excessive pressure on the primer of the cartridge in front of it and thus igniting the cartridges in the magazine.

Today there are bullets with almost every possible combination of bullet shape and shell construction.

Full and jacketed bullets

In the case of projectiles for handguns, a distinction is made between full projectiles (e.g. lead projectiles or solid projectiles) and jacketed projectiles .

Jacketed bullets are divided into full jacketed bullets (jacket completely encloses the tip and is mostly open at the bottom) and partial jacketed bullets (jacket is open at the tip and closed at the bottom).

Full floor

Full floors are floors made of a homogeneous material d. that is, they are jacketed bullets. The most common form of full bullets are simple lead bullets, such as those found in the sporting field ( diabolos for air guns ; lead bullets for small-caliber ammunition ), but also as shotgun barrel projectiles for shotguns.

There are also lead-free full bullets , mainly for hunting . These consist of copper or copper / zinc - alloys (. Eg brass or tombak ). They are manufactured either using automatic lathes or presses .

A special feature are full steel floors, which do not show any deformation in the active medium and release all of their energy via deep penetration. There are also so-called "frangible" ammunition, the projectile of which consists of a metal powder pressed under very high pressure without the addition of lead, which was specially developed for indoor stands.

Full jacketed bullets

Full jacketed bullets consist of a deformable jacket, usually made of tombac , and a core usually made of lead. The deformable jacket should be able to adapt to the swirling lines and fields in the pipe and keep its wear as low as possible. The core in turn forms the weight-giving mass. The effect in the target is generated by the destructive force of this very mass, which hits the target at the highest possible speed. It should damage or partially destroy the target by impact or entry and the associated energy release.

According to the Hague Land Warfare Regulations, military projectiles (army ammunition) are always full-jacketed projectiles, sometimes with a core made of uranium ( uranium ammunition ) or tungsten in order to increase the penetration power on armored material.

Semi-jacketed bullets

The semi-jacketed bullets make up the largest share of the bullets on the market. Most hunting bullets are partial jacketed bullets z. B. RWS cone point (KS), double core (DK) or Norma PPC Oryx or plastic point, as the shell, which is open at the front, ensures that the bullet breaks down when it penetrates the game. This transfers the projectile energy to the target and enlarges the wound canal. The probability that the game will be fatally hit increases. Full jacketed bullets, on the other hand, have a higher penetration rate and leave a smooth wound canal. This higher penetration rate is mostly used in the military sector. Partial jacketed bullets are forbidden in the military sector according to Article 23 of the Hague Land Warfare Regulations, “Prohibition of weapons and projectiles that cause unnecessary suffering”.

caliber

ASPI values ​​according to Alphin (Anglo-Saxon measurement system) [ft * lb * in²]
ASPI values ​​metric [Jmm²]

The diameter of the barrel, measured from field to field, is called the caliber . It should be noted that smaller calibers have established themselves in the field of military handguns. On the one hand, this enables a larger supply of ammunition to be carried, and on the other hand, the lower recoil improves the controllability of the weapon during bursts of fire . Due to the greater speed, smaller calibers have a higher penetration power than larger calibers (with the same projectile energy but smaller diameter, higher energy density J / mm²; see MP5 and MP7 ). But since a smaller caliber is accompanied by a smaller propellant charge, it is lower; see 7.62 × 51 mm NATO in relation to 5.56 × 45 mm NATO . The lower weight of the bullet also makes the bullet prone to deflection by slight obstacles in the bullet's trajectory such as grass or thin branches. Today's military standard rifle cartridge from NATO has a projectile with a diameter of 5.56 mm ( .223 Remington ). From a standard M16 rifle , the projectile of the above 5.56 × 45 mm cartridge reaches a muzzle velocity (v 0 ) of approx. 990 meters per second, which is reflected in the short and medium distances due to the faster (flatter) trajectory of the projectiles has a positive effect on hit performance.

Energy from projectiles

The behavior of projectiles is described by ballistics . The energy of a bullet immediately after leaving the barrel ( muzzle energy ) is calculated using the formula for kinetic energy : ${\ displaystyle E_ {0}}$

${\ displaystyle E_ {0} = {\ frac {1} {2}} mv_ {0} ^ {2}}$

The energy is given in joules , the mass of the projectile in kilograms and the muzzle velocity of the projectile in m / s . Due to the energy loss during the flight, the calculated energy value does not provide any information about the projectile effect at a certain distance, about its possible man-stopping effect or its effectiveness against armored or unarmored targets. ${\ displaystyle m}$${\ displaystyle v_ {0}}$

The muzzle velocity and the muzzle energy depend on many factors, such as the barrel length of the firearm , the type and weight of the bullet, the amount and type of powder charge ( load ) of the respective cartridge, and much more. Depending on the desired properties of the ammunition, there are also different loads for a single cartridge type possible, which also results in different muzzle velocities and energies when firing from the same weapon. Here is a short list of the performance data of some cartridges that can be achieved with common factory loads:

 caliber Mass of the projectile Muzzle velocity Muzzle energy 6 mm airsoft ball (6 mm BB) ~ 0.12 - 0.85 g ~ 70 - 100 m / s ~ 0.3 - 4.25 yrs 4.5 mm diabolo ( air rifle ) ~ 0.5 g ~ 90 - 360 m / s ~ 2 - 50 y .22 lfB ( small bore ) ~ 2.2 - 2.6 g ~ 300 - 340 m / s ~ 100 - 250 years 4.6 × 30mm ( PDW ) ~ 2.0 - 2.5 g ~ 725 m / s ~ 500 - 525 yrs 5.7 × 28 mm ( PDW ) ~ 1.8 - 2.1 g ~ 520 - 760 m / s ~ 470 - 540 yrs 9 × 19 mm ( pistol , MP ) ~ 7.5 g ~ 350 - 450 m / s ~ 300 - 550 J. .45 ACP ( pistol , MP ) ~ 12.0 g ~ 260 m / s ~ 320 - 600 J. 7.62 × 39 mm ( middle cartridge , e.g. AK-47 ) ~ 8.0 - 10.0 g ~ 610 - 745 m / s ~ 1,960 - 2,180 years 5.56 × 45 mm NATO ( assault rifle ) ~ 3.5 g ~ 1,000 m / s ~ 1,200 - 1,900 yrs 7.62 × 51 mm NATO ( rifle cartridge ) ~ 9 - 9.6 g ~ 700 - 900 m / s ~ 2,700 - 3,580 years 12.7 × 99 mm NATO ( heavy machine gun ) ~ 46.0 g ~ 800 m / s ~ 15,000 yrs 23 × 115 mm ( machine gun ) ~ 175 - 200 g ~ 690 - 740 m / s ~ 46,700 yrs 30 × 165 mm ( machine gun ) ~ 400 g ~ 980 m / s ~ 190,000 yrs 250 mm (10 ″) ball bomb in large fireworks ~ 4,500 g ~ 110 m / s ~ 55,000 yrs 120 × 530 mm ( DM 53 ) ( Leopard 2 tank ) ~ 5,000 g ~ 1,750 m / s ~ 7,650,000 yrs

For comparison: a locomotive with a mass of 50 tons and a speed of 80 km / h (22.2 m / s) has a kinetic energy of around 12,000,000 J.

A formula for approximating the penetration power of bullets was already developed by Isaac Newton, see also armor formula for estimating the penetration power of solid jacketed bullets in sheet steel. With regard to the stopping effect of projectiles, the A-Square Shock Power Index is often used.

literature

• Freiherr von Inn- und Knyphausen: The development of the infantry projectiles , in Kriegstechnische Zeitschrift, Mittler & Sohn, Berlin, 1907, pages 161-170. ( online at archive.org )