Handgun Effectiveness
Encyclopedia
Handgun effectiveness is a measure of the stopping power
Stopping power
Stopping power is a colloquial term used to describe the ability of a firearm or other weapon to cause a penetrating ballistic injury to a target, human or animal, sufficient to incapacitate the target where it stands....

 of a handgun
Handgun
A handgun is a firearm designed to be held and operated by one hand. This characteristic differentiates handguns as a general class of firearms from long guns such as rifles and shotguns ....

: its ability to incapacitate a hostile target as quickly and efficiently as possible.

Overview

Most handgun projectiles have significantly lower energy
Energy
In physics, energy is an indirectly observed quantity. It is often understood as the ability a physical system has to do work on other physical systems...

 than centerfire rifle
Rifle
A rifle is a firearm designed to be fired from the shoulder, with a barrel that has a helical groove or pattern of grooves cut into the barrel walls. The raised areas of the rifling are called "lands," which make contact with the projectile , imparting spin around an axis corresponding to the...

s. What they lack in power, they make up for in concealability and practicality. The lack of power they possess, and caliber/bullet effectiveness, are widely debated topics with growing experimental research among civilians, law enforcement, ammunition companies, and the military. One significant factor in bullet performance is velocity, and that relates in a given cartridge/caliber to barrel length of the firearm used.

Cavitation

Most handgun projectiles wound
Wound
A wound is a type of injury in which skin is torn, cut or punctured , or where blunt force trauma causes a contusion . In pathology, it specifically refers to a sharp injury which damages the dermis of the skin.-Open:...

 primarily through the size of the hole they produce. This hole is known as a permanent cavity
Permanent cavity
Permanent cavity refers to the hole left by the passage of a projectile. It is measured as the volume of tissue or ballistics gel that has been displaced by the passage of a bullet.- See also :* Terminal ballistics* Forensic ballistics* Stopping power...

. For comparison, rifles wound through temporary cavitation as well as permanent cavitation. A temporary cavity is also known as a stretch cavity. This is because it acts to stretch the permanent cavity, increasing the wounding potential. The potential for wounding via temporary cavity depends on the elasticity of the tissue, bullet fragmentation, and the rate of energy transfer. Many handgun bullets do not create significant wounding via temporary cavitation, but the potential is there if the bullet fragments, strikes inelastic tissue (liver, spleen, kidneys, CNS), or if the bullet transfers over 500 ft.lbf of energy per foot of penetration. These phenomena are unrelated to low-pressure cavitation
Cavitation
Cavitation is the formation and then immediate implosion of cavities in a liquidi.e. small liquid-free zones that are the consequence of forces acting upon the liquid...

 in liquids.

Penetration

There are many factors used to measure a handgun's effectiveness. One of them is penetration
Penetration (weapons)
Strictly speaking penetration occurs when a projectile enters a target without passing through it and perforation occurs when the projectile completely passes through the target, but the word penetration is commonly used to refer to either....

. The FBI's requirement for all service rounds is 12 inches (30 cm) penetration or greater in calibrated ballistic gelatin
Ballistic gelatin
Ballistic Gelatin is a testing medium scientifically correlated to swine muscle tissue , in which the effects of bullet wounds can be simulated. It was developed and improved by Martin Fackler and others in the field of wound ballistics. Ballistic gelatin is a solution of gelatin powder in water...

. This generally ensures a bullet will reach the vital organs from most angles. Penetration is arguably the most important factor in handgun wounding potential, because the vital areas must be destroyed or damaged to incapacitate.

Ballistic Pressure Wave/Hydrostatic Shock

There is a significant body of evidence that Hydrostatic shock
Hydrostatic shock
Hydrostatic shock or hydraulic shock describes the observation that a penetrating projectile can produce remote wounding and incapacitating effects in living targets through a hydraulic effect in their liquid-filled tissues, in addition to local effects in tissue caused by direct impact...

 (more precisely known as the ballistic pressure wave) can contribute to handgun bullet effectiveness.

Recent work published by scientists M Courtney and A Courtney provides compelling support for the role of a ballistic pressure wave in incapacitation and injury.
This work builds upon the earlier works of Suneson et al. where the researchers implanted high-speed pressure transducers into the brain of pigs and demonstrated that a significant pressure wave reaches the brain of pigs shot in the thigh.
These scientists observed neural damage in the brain caused by the distant effects of the ballistic pressure wave originating in the thigh.

The results of Suneson et al. were confirmed and expanded upon by a later experiment in dogs
which "confirmed that distant effect exists in the central nervous system after a high-energy missile impact to an extremity. A high-frequency oscillating pressure wave with large amplitude and short duration was found in the brain after the extremity impact of a high-energy missile . . ." Wang et al. observed significant damage in both the hypothalamus and hippocampus regions of the brain due to remote effects of the ballistic pressure wave.

Caliber

Another factor is expansion and caliber. Many civilians and practically all law enforcement agencies use jacketed hollow point or some form of expanding ammunition. This increases the chance of a handgun bullet striking a vital organ, and increases blood loss. Because of this, two different calibers could theoretically produce almost identical incapacitation results, provided the two penetrate the same area, and the small caliber expands to the size of the larger.

It is generally agreed that most intermediate handgun calibers will perform similarly, since their wounding principles are the same. A list of many handgun calibers can be found at List of handgun cartridges.

One-shot stops

The only scientifically proven and biologically possible way to produce instant incapacitation is through destruction of the central nervous system
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...

 or brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

. This will usually cease all motor-related and voluntary actions. If the central nervous system is not damaged or destroyed, there will be no immediate incapacitation. To allow room for error, since a central nervous system hit is very unlikely, most people use expanding ammunition. This will increase the odds of striking a part of the central nervous system, and cause faster blood loss.

For example, a popular caliber in the United States is the .45 ACP
.45 ACP
The .45 ACP , also known as the .45 Auto by C.I.P., is a cartridge designed by John Browning in 1904, for use in his prototype Colt semi-automatic .45 pistol and eventually the M1911 pistol adopted by the United States Army in 1911.-Design and history:The U.S...

. It is the largest practical handgun caliber in use, featuring a bullet that is .452 inches in diameter. With well made expanding ammunition, a .452 bullet often expands to .70 caliber or larger. With a 9 mm Luger bullet, for example, its normal .355 diameter might be hoped to expand to .50 caliber or larger. This could give a preference for larger caliber bullets, as they do not rely on expansion as much as smaller caliber bullets do to provide incapacitation.

Bullet expansion in handguns is desirable not solely for incapacitation, but also so the bullet will not exit the target. An expanding bullet will stop in the target and "dump" all its energy there, rather than overpenetrating and possibly endangering people behind the target. Since all handgun rounds are marginal at best, the one with the most energy and which expends all that energy in a target is the one that is most effective.

External links

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