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Examination of Gunshot Residue

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Other Issues and Forms of Injury

Home Defense

Much is written in the popular literature concerning weapons for home defense, with articles recommending virtually any type of firearm short of a howitzer! Unfortunately, presence of guns in the home leads to more accidents and fatalities (often children) than to actual use in defensive situations. (Kellerman and Reay, 1986).

It should be remembered that most projectiles above .22 cal can penetrate the relatively thin wallboard of houses and apartments, and bullets fired from a military-style rifle might well penetrate through several houses! Perhaps the best weapon, if one were to pick an ideal based upon safety and ability to hit a target under duress, would be a short-barreled shotgun with shells containing small pellets (#6 or 7). (Zaleski, 1982)

Shooting Injuries

Persons engaged in target shooting, particularly at indoor firing ranges, but also at outdoor ranges, are exposed to lead and may develop intoxication with lead (Gelberg and Depersis, 2009). Other metals that accumulate at shooting ranges include copper, antimony, and zinc. (Strømseng et al, 2009) Blood lead levels in persons exposed to environments at firing ranges may exceed acceptable standards. Women and children may not receive the same health protections as occupational users. Safety measures include clothing changed after shooting, banning of smoking and eating at firing ranges, improved ventilation and airflow systems, and using lead-free primers and lead-free bullets. (Laidlaw et al, 2017) Use of frangible bullets, typically composed of a metal powder other than lead, such as copper, reduces exposure to lead. Use of a total metal jacket (TMJ) bullet reduces lead exposure, particularly in indoor ranges. (Komenda et al, 2013)

Bullet removal may not occur in victims of gunshot injuries with retained bullets or bullet fragments unless there is risk for immediate problems. Bullets lodged in soft tissues tend to become encased in scar tissue to reduce potential for lead poisoning, but the risk is greater when bullets are retained within a joint space, bone, or intervertebral disk, and with a greater number of fragments, fractures, and formation of cysts. Injuries which result in retained bullet fragments carry a small but identifiable risk for lead poisoning, defined as blood lead ≥10 μ/dL. In adults, lead poisoning may lead to nonspecific problems including chronic fatigue, abdominal pain, and diminished mental function. In the U.S. retained bullet fragments may account for 0.3% of all elevated blood lead levels in adults, and high levels ≥80 μ/dL are more likely to occur in these persons. (Weiss et al, 2017) (Baum et al, 2022)

The median blood lead level of persons with retained bullet fragments was 9.01 μg/dL in one study, exceeding the ≥ 5 μg/dL Center for Disease Control definition of elevated BLL. Fragmentation or multiple bullets may increase lead-tissue surface area contact) with higher risk of elevated BLLs. In addition, potential delayed local complications of retained bone and soft tissue bullets or bullet fragments include mechanical irritation, foreign-body reactions, and delayed infection. Intra-articular bullets have potential to fragment and dissolve due from mechanical forces and solubilization of lead by acidic synovial fluid, leading to inflammatory and possible destructive foreign-body reactions, mechanical articular cartilage damage, and secondary degenerative joint disease. (Kani et al, 2022)

Brachial plexus injuries have been reported from firearm recoil. (Wanamaker, 1974) Eye protection (glasses or goggles) should be worn when target shooting to prevent eye injury from ammunition fragments (Heimann and Lemmen, 1986).

A ported barrel has slots cut at the top near the muzzle to release gas behind the bullet in order to reduce muzzle lift. Reduced lift would be advantageous in keeping the gun more level on target when multiple rounds are fired in succession. However, the hot gas released is closer to the shooter and may direct particles of unburned powder, lead, or jacket materials back toward the shooter, or toward a bystander if the gun is not perpendicular.

"Less Lethal" Ammunition

Law enforcement agencies desire to immobilize persons they are pursuing while trying to avoid injury to bystanders. These agencies, and national armed forces, in the process of crowd control during public demonstrations of dissent, also try to employ projectiles designed to incapacitate but not kill. Ammunition used for these purposes is designed to have large dimensions so that impact occurs without penetration to deliver enough kinetic energy for "stopping power".

Such ammunition includes:

  • Rubber balls

  • lead shot enclosed in a fabric bag ("bean bag")

  • Rubber slug

  • Plastic bullets or buckshot

  • Rubber-coated metal buckshot

Injury patterns include lacerations, fractures, and penetrations. Shorter firing distances lead to greater injuries. (Wahl, Schreyer and Yersin, 2006) (Masahiko and Mellen, 2009)

Air guns may include "BB" guns that shoot round steel projectiles, which may be copper coated, generally of 0.17 caliber, and may include air rifles that can shoot not only BB projectiles, but also 0.17 caliber pellets of various shapes, including round nose, pointed, wadcutter, or flat, as shown:

The most common shape is the "wasp waist" or "diablo" style.

Though small "BB" pellets may produce injuries. The standard steel "BB" is 0.173 to 0.177 caliber (4.4 to 4.5 mm), and standard velocities may range from 200 to 400 feet per second. In a study by DiMaio et al, with "wasp waist" pellets of 0.177 caliber, at 290 fps, there was penetration of skin (pellet embedded in skin), and at 331 fps (101 mps) there was perforation through the skin. At 365 fps and higher, perforation always occurred (DiMaio et al, 1982).

There is a theoretical penetration depth of 36 mm into solid bone with pellet projectiles fired at contact range. At longer ranges the velocity and kinetic energy dissipate quickly. If the projectile rolls back and forth in the air rifle barrel, an air cushion can develop between projectile and breech block, reducing muzzle velocity by ore than half and reducing wounding potential. (Kamphausen et al, 2019)

The greatest risk for tissue injury with such projectiles is the eye. In a study of "BB" pellets weighing 5 grains fired from a distance of 10 feet at pig eyes determined that a minimum velocity of 246 fps was required to cause corneal perforation with penetration to the retina (Powley et al, 2004).

"Airsoft" ammunition is a slightly bigger plastic or metal versions of a "BB" pellet. The average velocity of air guns firing such projectiles is 366 fps. Such projectiles include 6 mm in diameter plastic pellets that are 0.11 or 0.25 gm, 6 mm metal spheres weighing 0.3 gm, and 8 mm plastic spheres weighing 0.34 gm. In one study of potential eye injury, it was shown that when firing fromn a distance of 2 inches at a pig eye, that penetration of the cornea occurred at 403 fps for the 6 mm pellets weighting 0.11 gm, 325 fps for 0.25 gm 6 mm pellets, and 373 fps for the 8 mm plastic pellets; the 6 mm metal pellets penetrated at 331 fps.

Some law enforcement agencies have adopted "bean bag" projectiles to lessen the potential for injury. Such projectiles consist of a fabric or nylon bag filled with lead shot, and are designed to be nonpenetrating. However, serious injury is possible (Grange et al, 2002).

Plastic bullets, replacing rubber bullets (implicated in three deaths) used as "safe" projectiles for riot control, were shown in one study to be associated with 13 deaths (seven children) by serious head injury, usually when fired at distances less than the 25 yard range considered be "safe" (Metress and Metress, 1987)

Frangible bullets, composed of a metal such as copper powder that is compacted, are designed to fragment on impact, lessening penetration and reducing potential injury to those nearby. The wounding properties are variable. (Komenda et al, 2013)

Exit wounds are uncommon, given the low energy levels of these projectiles. When penetration occurs, the projectiles lodge within tissues. Rare reports of pellet emboli have been reported, and surgical procedures for removal are not without risk for morbidity and mortality (Misseldine and August, 2010).

Blank Cartridge Injuries

Blank cartridges are intended to produce noise, and are designed to do so via use of ultra-fast burning powder that detonates rather than burns. Blank pistols are not considered firearms in most countries. Such pistols may be used in criminal activities because they appear to be "real" to intimidate victims. Such guns can be modified by removing the obstruction in the barrel to accomodate small balls placed inside the cartridge or handmade projectiles inserted into the tip of the cartridges. Not only such projectiles, but also the propellant gases can produce severe and even lethal injuries. Fatal injuries typically involve head, neck, and chesst. (Demirci et al, 2011)

Guns firing blanks typically have the barrel blocked, and they may produce a backspatter of biologic material propelled from an entrance site or wound backwards toward the shooter, onto hands or other body parts. The backspatter may persist inside parts of the weapon, even after cleaning. The gas jet created from firing a blank gun carries enough energy to penetrate skin and produce a temporary cavity at contact range. DNA can be collected for analysis from the inner and/or outer surfaces of the blank-firing weapons. (Euteneur et al, 2021)

Noise-related Injury

Firearms produce sudden noise. The noise is in the form of an impulse upon the ear. The amount of noise produced and the potential for auditory injury depends upon complex variables. The type of firearm and the type of ammunition used, as well as the number of rounds, determines the noise exposure. In general, guns with small caliber and long barrel and guns with the least powerful ammunition tend to be associated with the least auditory risk. Unprotected exposure to firearm noise is not advised (Flamme et al, 2009).

A muzzle brake, or compensator, is positioned at the end of the barrel and redirects gases outward and forward. This aids in reduces the recoil and rise of the barrel. However, gases and particulates, as well as sound, are partly directed back to the shooter so that eye and ear protection are needed.


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Examination of Gunshot Residue

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