There are many types of wounds related to firearm as listed below:
Atypical Entrance Wound
(a) For a few microseconds after the bullet leaves the muzzle (up to about 50 meters for a pistol or 150 meters for a rifle), there may be a “tail wobble’ or “tail wag”. This is partly responsible for the great tissue damage and the large atypical entrance wound at short range.
(b) The gyroscopic effect diminishes as it reaches the end of its ugh, until it begins to wobble, and then to tumble. In wobble, yaw or tumble, the impact of it may be sideways or even backwards with an irregular lateral motion, due to which an irregular lacerated wound is produced. The one traveling in an irregular fashion instead of traveling nose-on is called a YAWNING BULLET, and a bullet that rotates end-on-end during its motion is called a TUMBLING BULLET. The amount of tissue crush might be three times greater when the bullet yaws to 90°.
(c) The tattooing seen on the skin may be altered by the use of ‘silencers’. Muzzle-brakes and flash hiders may produce peculiar blackening and tattooing patterns by allowing gases to pass in specific direction. Bullets fired through a shortened barrel, may be deformed or squeezed.
(d) In revolvers, weapon defects, such as cylinder misalignment will cause deformities of the missile, with breaking off of the metal fragments from it occurring when the misalignment is great. Lesser defects of this type may cause tumbling.
(E) RICOCHET BULLET : A ricochet bullet is one which before striking the object aimed at, strikes some intervening object first, and then after ricocheting and rebounding (glancing) from these, hits the object. They are rare, as most bullets on striking a hard surface break up or penetrate the surface. The critical angle of impact for ricochet for hard surfaces varies from 10 to 30°. It ricochets off at an angle smaller than the impact angle. It may ricochet before or after striking the body and may produce a non-penetrating or a penetrating injury.
Ricocheting of it may occur with inferior firearms and low velocity bullets. It may be deformed and flattened before striking the skin. The degree of deformity varies depending on the texture of it.
This produces a large irregularly oval, triangular or cruciate entrance wound with irregular abraded margins. As it loses gyrating movements, abrasion collar is absent. Burning, blackening and tattooing are also not seen.
Sometimes, it may strike an object and tumble, and hit the body side on, producing an elongated wound of entrance like a keyhole. The path of a ricochet is completely unexpected. Particles of the substance against which it is deflected or has struck, e.g., soil, fibers, paints, etc. may be found adhering to it.
The nose of it may be found facing the entrance wound due to deflection in the body. When the velocity is lost, it only produces an abrasion or contusion.
Sometimes, after passing through the brain, there is not enough energy left in it to penetrate the skull. It may rebound (ricochet) from the inner table of the skull like a billiard ball, producing a second track. If it ricochets for a second time, a third wound track is produced.
If it enters the skull at an acute angle towards the inner table, it may move along the dura tearing the leptomeninges and blood vessels and produce a shallow wound track along the surface of the brain. The inner divergent course of it may be combined with internal ricochet.
(f) The bullet may strike the surface producing a contusion and fall to the ground. This is seen with relatively soft non-jacketed bullet fired from a firearm that has an eroded or worn barrel; and also when the ammunition used is of smaller size than the barrel of the gun.
(g) Bullet Graze or Slap : If it strikes skin at so acute an angle that it does not perforate the skin, a grazing or slap wound is produced. It usually appears as reddish-brown, elongated, elliptical or triangular furrow or abrasion. The underlying dermis may or may not be involved, but the adjacent intact skin may be ecchymosed.
(h) The bullet strikes the sternum at just the right angle and is deflected, so that it continues around the rib cage, between the bone and the skin. It may come out at the back of the body after causing only a superficial injury; or it may lodge between the skin and the backbone.
Bullets that strike in unusual location may cause injury and death, but the wound of entry may be difficult to locate, e.g., ear, nostril, mouth, axilla, vagina and rectum.
Single entrance and multiple exits
If the bullet splits up within the body and divides itself into 3 or 4 pieces, there will be only one entry hole, but several exits. The bullet striking a bone may break the bone into fragments, which act as secondary missiles producing multiple exits. Sometimes, the jacket of it may separate from the inner part upon impact on bone. In such cases, the jacket and the core each produce separate tracks.
With the semi jacketed bullet, lead core usually exits, and the jacket remains in the body. Sometimes, a fragment of metal separates from it during its passage through the skull. The separated fragment proceeds under the skin until it exits at a distance of 3 to 5 cm. or remains lodged between the skull and the skin.
The major part of the bullet will enter the skull and may exit in a different position. In such a case, a single one will produce two exit wounds. In bullet wounds of the head, many lead fragments may be found scattered throughout the brain and on X-ray may closely resemble a shotgun injury.
Bullet Striking the Skull but not entering it
Bullets may graze or rub the top and sides of the cranium without entering it. In such cases, entry and exit wounds are found on the scalp about two to three cm. apart, while the skull between the two wounds shows an oval or elongated gutter-like depression (gutter wound; key-hole defect).
When the bullet strikes the skull at an angle, it may rarely deviate from its path by impact on the bone, to produce a continuous wound track .under the skin without penetration of the skull. The track may proceed for considerable distance, the bullet following the curvature of the skull.
Multiple Wounds of Entrance and Exit from a Single Shot
A bullet may pass through an arm and the chest so that four wounds result. A bullet passing through the chest or abdomen and thigh and lower leg, produces six wounds. This occurs when the person is running or sitting in an unusual position.
When the body surface is irregular, such as the breast or buttocks, several re-entries and exits can take place. In such cases, examination of clothing and detection of nitrites and nitrates and microscopic examination of the sections of the wound is useful. The features of re-entry wound resemble those of wounds caused by long range fire.
Entrance Wound is present but Bullet is not found in the Body
This occurs when
Unexplained Bullets in the Body Occasionally, more bullets are found than there are entrance wounds. This occurs, due to defect in the weapon, or due to faulty ammunition, or with loaded firearm unused for several years.
When such a weapon is fired, it may fail to come out from the muzzle. When it is fired again, the second one may go off carrying the lodged with it, and both may enter the body through the same entrance wound.
This is called a tandem or piggyback bullet (tandem=one behind the other). The bullets may separate within the body, or before they hit the target. The features caused by flame, smoke and gunpowder may be diminished or absent and the wound may appear as if caused by long-range fire.
This is because the pushing force of the second one is directed backwards due to obstruction caused by first one impacted in the barrel.
If it is present for a long time in the body, there will be no fresh bleeding in the surrounding area. A dense fibrous tissue capsule usually surrounds it. A small scar indicates the original entrance wound. Lead poisoning may occur due to absorption of lead from lead bullets remaining in a body. Synovial fluid is capable of dissolving lead.
Fatalities with Blank Cartridges
A blank cartridge is one containing primer, gunpowder and wadding, but without it or pellets. It contains ultra fast burning powder that explodes rather than burns. Wounds can be caused from the gases or from the closing part in the end of the cartridge.
Wadding or gunpowder may cause laceration and may produce death from shock by pressure on nerves or by damaging main vessels, when blank cartridge is discharged close to the body. Distant shots with blank cartridge are harmless.
Firearm going off by itself
The firearm can go off by itself without any one touching the trigger due to some defect in its mechanism. Country-made guns and old worn guns may discharge on being pushed or thrown, or by the butt being dropped against the ground.
They are designed to fragment upon impact, often to the point of disintegration. They are made mostly by lead or iron. Recovery and matching with a test bullet is difficult. If bone is penetrated, they are usually recovered in an eroded state. They do not ricochet.
In some bullets, the component parts tend to separate on impact. Such bullets are partially jacketed at the base, with the tip remaining an uncovered lead core. The components separate on striking the body and create their own tracks.
Duplex or Tandem Cartridge
This is used in military rifles, and contains two bullets which enter the target at different points, separated by as much as 30 cm. The base of the forward one is notched, into which the second bullet fits closely. The base of the ‘follow’ bullet is not quite at right angle to its long axis, due to which there is a difference in line of movement of both.
Surgical alteration or suturing of gunshot wounds create problems. The evaluation of the wound, whether it was an entrance or an exit wound becomes difficult (Kennedy phenomenon).
Those entering an artery embolise into the femoral and popliteal arteries. With less frequent venous embolism, bullets enter veins of the lower limb or heart.
Concealed Firearm Wounds
If the body is covered with blood, the blood clots may obscure the injury. A wound in the mouth, nostril, ear, eye, or in any of the body orifices, e.g. rectum or vagina may not be detected, if due care is not taken.