# Bullet energy

Projectile energy is a term of ballistics and called kinetic energy of the projectile . The bullet generally has the highest energy when it leaves the muzzle .

## calculation

The kinetic energy is calculated as , with the projectile mass m G (kg) and the projectile speed v G (m / s). It is given in joules (J). ${\ displaystyle {\ frac {1} {2}} \ cdot m _ {\ rm {G}} \ cdot v _ {\ rm {G}} ^ {2}}$

An old unit is mt (meter · ton) in the sense of (meter · 1000 kp). In Anglo-Saxon countries, the unit foot-pound is used for projectile energy instead of joule .

## Muzzle energy

Muzzle energy (also known as muzzle force) describes the kinetic energy of the projectile when it leaves the barrel of a weapon .

Shooting ranges are always approved for weapons with a certain maximum muzzle energy.

Firearms whose projectiles are propelled by cold gases (air pressure and CO 2 weapons), i.e. without NC or black powder, with a muzzle energy that is less than 7.5 joules can be purchased in Germany from the age of 18.

## Impact energy

Impact energy describes the kinetic energy of the projectile when it hits the target. Because of the air resistance , it is less than the muzzle energy. An old term is impact force.

## Examples

• The rifle Fortek 2001 verschießt ammunition from Caliber .50 BMG , that is 0.5  inch  = 12.7 mm in diameter, and a projectile mass of 42 g with a muzzle velocity of 823 m / s. The muzzle energy is thus 14,224 J. The maximum firing range of 6200 m is achieved with this ammunition at a firing angle of 37 degrees. The projectile hits at a speed of 175 m / s and thus has an impact energy of 643 J.
• The fat Bertha , a large mortar from the First World War , fired HE shells of up to 1200 kg with a maximum muzzle velocity of 435 m / s and thus achieved a muzzle energy of 114 MJ. The shell hit after about 9 km at 310 m / s and thus had an impact energy of 58 MJ. This corresponds to the kinetic energy of a mass of 1200 kg, which falls from a height of 5000 m to the earth without being slowed down by air resistance, or from 4 railway wagons of 50 t each at a speed of 86 km / h or one of these wagons 172 km / h, which it would reach after falling from a height of 120 m.

### Table of selected floors

 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

## Individual evidence

1. ^ The ammunition of the German 120 mm tank cannon from Rheinmetall. Stefan Kotsch, accessed April 17, 2009 . (Weight of penetrator )
2. Paul-Werner Krapke: Leopard 2 - his becoming and his performance . BoD - Books on Demand, 2004, ISBN 3-8334-1425-1 , pp. 8 ( limited preview in Google Book Search [accessed April 17, 2009]).