At high velocity, generated shock waves can reach up to atmospheres of pressure. DiMaio and Zumwalt, However, bone fracture from cavitation is an extremely rare event. Fackler, The ballistic pressure wave from distant bullet impact can induce a concussive-like effect in humans, causing acute neurological symptoms. Courtney and Courtney, The mathematics of wound ballistics, in reference to yaw of unstable projectiles, has been described.
The model works well for non-deformable bullets. Peters et al, Peters and Sebourn, Experimental methods to demonstrate tissue damage have utilized materials with characteristics similar to human soft tissues and skin. Pigskin has been employed to provide an external layer to blocks of compounds such as ordnance gelatin or ballistic soap.
Firing of bullets into these materials at various ranges is followed by direct visual inspection cutting the block or radiographic analysis CT imaging to determine the sizes and appearances of the cavity produced Rutty, et al, The following images illustrate bullet deformation and damage:.
Bullet velocity and mass will affect the nature of wounding. Wilson, An M rifle. A hunting rifle. Bullet design is important in wounding potential. The Hague Convention of and subsequently the Geneva Convention forbade the use of expanding, deformable bullets in wartime. Therefore, military bullets have a full metal jacket FMJ around the lead core.
Such bullets are typically made of a metal other than lead, such as copper powder compacted into a bullet shape, as diagrammed below:. The distance of the target from the muzzle plays a large role in wounding capacity, for most bullets fired from handguns have lost significant kinetic energy KE at yards, while high-velocity military.
Military and hunting rifles are designed to deliver bullets with more KE at a greater distance than are handguns and shotguns. The type of tissue affects wounding potential, as well as the depth of penetration. Bartlett, Specific gravity density and elasticity are the major tissue factors. The higher the specific gravity, the greater the damage. The greater the elasticity, the less the damage.
Thus, lung tissue of low density and high elasticity is damaged less than muscle with higher density but some elasticity. Liver, spleen, and brain have no elasticity and are easily injured, as is adipose tissue. Fluid-filled organs bladder, heart, great vessels, bowel can burst because of pressure waves generated. The speed at which a projectile must travel to penetrate skin is fps and to break bone is fps, both of which are quite low, so other factors are more important in producing damage.
Belkin, Designing a bullet for efficient transfer of energy to a particular target is not straightforward, for targets differ. To penetrate the thick hide and tough bone of an elephant, the bullet must be pointed, of small diameter, and durable enough to resist disintegration.
However, such a bullet would penetrate most human tissues like a spear, doing little more damage than a knife wound. A bullet designed to damage human tissues would need some sort of "brakes" so that all the KE was transmitted to the target. It is easier to design features that aid deceleration of a larger, slower moving bullet in tissues than a small, high velocity bullet. Such measures include shape modifications like round round nose , flattened wadcutter , or cupped hollowpoint bullet nose.
Round nose bullets provide the least braking, are usually jacketed, and are useful mostly in low velocity handguns. The wadcutter design provides the most braking from shape alone, is not jacketed, and is used in low velocity handguns often for target practice.
A semi-wadcutter design is intermediate between the round nose and wadcutter and is useful at medium velocity. Hollowpoint bullet design facilitates turning the bullet "inside out" and flattening the front, referred to as "expansion. A frangible bullet composed of a powder is designed to disintegrate upon impact, delivering all KE, but without significant penetration; the size of the fragments should decrease as impact velocity increases.
The FMJ bullet has exposed lead at the base of the bullet. The TMJ bullet is fully covered with a copper plating. Also, the TMJ reduces the amount of lead contaminants expelled into the air, which is an advantage in indoor ranges.
A TMJ bullet is not recommended for ported firearms, because there is an increased likelihood that part of the casing may be sheared off as the bullet leaves the barrel. These weapons are easily concealed but hard to aim accurately, especially in crime scenes.
Usually, low caliber weapons are employed in crimes because they are cheaper and lighter to carry and easier to control when shooting. Tissue destruction can be increased at any caliber by use of hollowpoint expanding bullets. Some law enforcement agencies have adopted such bullets because they are thought to have more "stopping power" at short range. Ragsdale, However, there is a myth, kept alive by portrayals of shooting victims on television and in films being hurled backwards, that victims are actually "knocked down" or displaced by being struck with the force of a bullet.
In fact, real gunshot victims relate that they had no immediate reaction. Fackler, The maximum momentum transferred from different small arms projectiles, inluding large caliber rifles and shotguns, to an 80 kg body is only 0. Karger and Knewbuehl, Incapacitation of gunshot victims is primarily a function of the area of the body wounded. Immediate incapacitation may occur with gunshot wounds to the brain and upper cervical cord.
Rapid incapacitation may occur with massive bleeding from major blood vessels or the heart. Karger, The two major variables in handgun ballistics are diameter of the bullet and volume of gunpowder in the cartridge case. Cartridges of older design were limited by the pressures they could withstand, but advances in metallurgy have allowed doubling and tripling of the maximum pressures so that more KE can be generated. Many different cartridges are available using different loads and bullet designs.
Some of these are outlined in the table below to compare and contrast the ballistics. What can be learned from specific cartridge data? If the 44 magnum is compared with the magnum, the effect of bore diameter is seen. The larger area of the 44 magnum creates more force with the same pressure, allowing the 44 magnum to produce more energy at the muzzle. The effect of case capacity can be demonstrated in a comparison of the 9 mm parabellum para with the magnum.
These cartridges have similar diameters and pressures, but the magnum is much longer, yielding more case volume more powder , and delivers more energy.
Finally, despite the Colt 45 having the largest bore diameter and one of the longest cases, it does not deliver the maximum energy because the outdated design of this cartridge case severely handicaps its pressure handling capability. The Glasser "safety slug" has been designed to consist of a hollow copper jacket filled with 12 birdshot. It has been designed in several calibers. When the bullet hits the target, the pellets are released over a wide area.
However, the pellets quickly decelerate over a short distance, so they may penetrate poorly and are less likely to hit surrounding targets. They are designed to stop, but not kill, an attacker while avoiding injury to bystanders. At close range, they may produce substantial injury. Binders provide all the holding power that keeps the primer in place. Some rimfire mixes differ from their centerfire counterparts by the addition of a frictionator helps ignition in the rimfire system , which may be finely ground glass.
The priming chemicals are blended in controlled facilities, often by remote control. Adding water to the mix makes it less dangerous to handle and allows the mass to be shaped. Even with these precautions, transporting primer mix is hazardous; cartridge cases are moved to the primer chemistry facility rather than moving the primer mix to the case loading location.
Modern bullet and cartridge designs have abandoned most of these principles, but you could never call these features unsuccessful. The antique. Like copper and copper-alloys like brass, soft metal could be rolled into thin sheet metal, then punched into small discs.
Hundreds of these little cups could be drawn and bumped in a single pass of a 19 th Century machine press. This made ammunition for the Model 1 widely available and affordable. Several U. By , annual round production hit 30 million. Later came the. First, the rim of a rimfire held the cartridge securely in the breech face. A closed action effectively clamped the round in place. A stout mainspring held tight enough.
Second, the ammunition was relatively weather-sealed with the bullet pressed in place surrounded by a copper case—a dramatic improvement over loose powder and paper cartridges. Fourth, the rim provided an excellent gripping surface for reliable extraction and ejection. Extraction and ejection issues plagued early needle-fires and pinfires. Fifth, the rim provided an effective way to measure and build proper headspace into bolts and barrels, which helped make the round accurate.
Headspace is the distance between the bolt face and the part of the chamber that prevents the case from moving forward. With a rimfire, the headspace is taken up by the thickness of the rim, which is sandwiched between the bolt face and the breech.
For all these reasons and more, patent offices in the U. In , B. Tyler Henry patented a rimfire repeater with a cartridge called the. By , repeating carbines utilizing. By , a catalog for Union Metallic Cartridge Company listed 40 rimfire cartridges for sale.
Only two were. More than half the list ranged between the Colt. Rimmed big-bore cartridges dominated small arms until the advent of smokeless powder required cartridges capable of handling high pressures.
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