Finally, the science of terminal ballistics helps engineers contrive bullets capable of striking the target with a variety of desired effects. Similarly, external ballistics allows engineers to create more aerodynamic firearm projectiles. Through the study of external ballistics, engineers can develop long range bullets which strike the target with great precision. Guns are nothing more than sophisticated, specially engineered machines. As the bullet moves down the barrel, it accelerates, and the pressure decreases slightly as a result of the expanding volume behind the bullet. The powder continues to burn, increasing the pressure in the chamber, until it reaches a maximum when the bullet is a short distance down the bore. At a certain point, the pressure in the cartridge exceeds the friction that holds the bullet in place, and it begins to move. As the pressure and temperature inside the cartridge increase, the rate of combustion increases, building up higher and higher pressure. As the powder in the cartridge burns, it produces hot gas which causes pressure to build in the cartridge. The primer ignites and shoots a 2000 degree C stream of fire into the cartridge, igniting the main power charge. A gun is fired by pulling the trigger which releases the firing pin from its cocked position allowing it to collide with the primer. The powder charge contained within the cartridge ignites by means of a percussion explosive contained within the primer. The firing of a bullet by a rifle is the first step in the ballistics process. To paraphrase Chris Rock in Bigger, Blacker and Uncut, if bullet prices were raised to $5,000 each, there would be a drastic decrease in murders. Also, individuals involved with clandestine operations may use firearms with silencers, which suppress bullet speed and require special subsonic ammunition. Pistol bullets generally feature a lower acceleration than rifles or machine guns. The acceleration of a bullet depends largely on the gun from which it is fired, along with the intent of the user. With its 127 mm barrel length, the bullet's acceleration is calculated to be 4.4 × 10 5 m/s 2. When fired from a Beretta 92S, the standard issue US Army pistol, a 9 mm Parabellum bullet has a muzzle velocity of 335 m/s. Since acceleration is the desired value, the derived formula is this: V o is the initial velocity of the bullet, which is zero Using a kinematics formula, it is possible to determine the acceleration of a bullet when the muzzle velocity and barrel length of a gun are known. While small in size (the most popular handgun bullet is 9 mm in diameter) bullets posses enough kinetic energy to cause serious damage. Contrary to popular belief, guns are not loaded with bullets, but cartridges, and they fire bullets (since bullets are a more common term and the actual objects responsible for harm, they receive the recognition). This causes a rapid expansion of gas, which forces the bullet forward and ejects the casing. When a gun trigger is pulled, the primer is struck, igniting the propellant. A typical cartridge consists of four components: the cartridge case, primer, propellant charge and bullet. However, their designs are all basically the same. There is also special ammunition capable of penetrating armor, firing underwater, or firing "silently" at subsonic speeds. They come in numerous varieties for use in handguns, rifles, and machine guns. Their main function is to kill or otherwise incapacitate. "Barrel length: 122.5 mm… The SS190 ammunition looks like a scaled down 5.56 mm NATO round and boosts the 2.02 gram (31 grains) pointed steel and aluminum core bullet to the muzzle velocity of 650 meters per second from the pistol barrel."īullets are cylindrical metal projectiles shot from firearms. Fabrique Nationale (FN) Five-seveN (Belgium). London, United Kingdom: Salamander House, 1981. An Illustrated Guide to Pistols and Revolvers. "7.21 Firebird Factory Ballistics (27 inch barrel)… Velocity: 3950 " "If a bullet leaves the muzzle of a rifle with a speed of 600 m/s, and the barrel of the rifle is 0.9 m long, what is the acceleration of the bullet while in the barrel?"īadness, Frank C.
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