In 1742, Benjamin Robins invented the ballistic pendulum. This is the precursor to the concept of the "standard projectile". Johann Bernoulli took up this challenge and soon thereafter solved the problem and air resistance varied as "any power" of velocity known as the Bernoulli equation. Keill gave no solution for his challenge. This challenge supposes that air resistance increases exponentially to the velocity of a projectile. In 1718, John Keill challenged the Continental Mathematica, "To find the curve that a projectile may describe in the air, on behalf of the simplest assumption of gravity, and the density of the medium uniform, on the other hand, in the duplicate ratio of the velocity of the resistance". Newton's experiments were only at low velocities to about 260 m/s (853 ft/s). He showed that drag on shot increases proportionately with the density of the air (or the fluid), cross sectional area, and the square of the speed. Newton's experiments on drag were through air and fluids. Ĭirca 1665, Sir Isaac Newton derived the law of air resistance. This allowed Galileo to show that a bullet's trajectory was a curve. He found that a falling body had a constant acceleration. In 1636, Galileo Galilei published results in "Dialogues Concerning Two New Sciences". He noted that the shot trajectory was continuously curved. In 1537, Niccolò Tartaglia performed test firing to determine the maximum angle and range for a shot. ( January 2021) ( Learn how and when to remove this template message) Unsourced material may be challenged and removed. Please help improve this article by adding citations to reliable sources in this section. Mc Graw-Hill encyclopedia of Science and Technology, volume ebe-eye and ice-lev, 9th Edition, Mc Graw-Hill, 2002.This section needs additional citations for verification. Obert, Thermodynamics, McGraw-Hill Book Co., 1948. 45 Colt ammunition can produce 1,200 foot-pounds of muzzle energy, far in excess of the average listed above.Įdward F. A 110 grain bullet fired from the same gun might only achieve 400 foot-pounds of muzzle energy, depending upon the manufacture of the cartridge. 357 magnum handgun can achieve a muzzle energy of 580 foot-pounds. While the above list mentions some averages, there is wide variation in commercial ammunition. Also note that the muzzle energy does not necessarily reflect how much energy is transmitted to the target. It must be stressed that muzzle energy is dependent upon the factors previously listed and that even velocity is highly variable depending upon the length of the barrel a projectile is fired from.
Typical muzzle energies of common firearms and cartridges Example muzzle energy levels of different types of firearmsĪverage muzzle energies for common pistol cartridges The bullet energy, remaining energy, down range energy and impact energy of a projectile may also be calculated using the above equations.
If m is specified in grains and v in feet per second, the following equation can be used, which gives the energy in foot-pound force:Į k = 1 2 m v 2 × ( 1 ft ⋅ lbf 7000 gr × 32.1739 ft 2 /s 2 ) Most sporting arms publications within the United States report muzzle energies in foot-pound force. Mass, m, is usually given in grains and the speed, v, in feet per second but kinetic energy, E k, is typically given in foot-pound force (abbreviated ft-lbf).If the mass, m, is in grams and the speed, v, is in kilometres per second, the calculated muzzle energy, E k, will be in kilojoules.
If the mass, m, is in kilograms and the speed, v, is in metres per second, the calculated muzzle energy, E k, will be in joules.2 Typical muzzle energies of common firearms and cartridgesĬare must be taken when using this formula that consistent units are used.
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