Shotgun wounds

Shotguns type:

• Gauge

• choke

Gauge

• Describes the caliber of the shotgun

• Equals the number of lead balls of the bore diameter that makes up a pound

• 12 gauge: 12 lead balls to make one pound

• The larger the gauge, the smaller the bore diameter

choke

• Partial constriction of the bore at its muzzle

• Controls shot patterns

• Full choke, modified choke, improved cylinder, cylinder

shotgun ammunition

• pellets or slug

• cup, wad, filler

• propellant

Characteristics of SGW

• gauge

• choke

• range of fire

• rifled or smooth bore

• sawed off shotguns

Range of fire (SGW) with a full choke

• Pellets and wad stay together for approx. 3 feet

• Was falls downward

• Pellets begin to spread approx. 3 feet

• Increase spread by one inch for every 3 feet

• At 40 yards, 65-75% of the shot falls in a 30-inch circle

Range of fire (SGW) with a modified, improved or no choke

• Pellets spread earlier

• No choke shotgun pellets spread widely with only 30-45% falling in a 30 inch circle at 40 yards while the remaining pellets have a wider spread

Range of fire (SGW)

• Intermediate targets affect pellet spread

• So called billiard ball effect

• Collision of slowed and oncoming pellets causes widespread dispersion making an estimation of the range difficult or impossible

• Body curves and the positioning of the body will affect spread as well.

Range of fire-contact wounds

• massive deformation, especially when they involve the head

• muzzle stamp present

Contact SGW head

• may have gunpowder on non dominant hand

• intraoral wounds usually have teas at the corner of the mouth

Intraoral

gunpowder and soot on palate, tongue

Contact SGW head

• charge of shot entering the skull

• gas from propellant

• wad of cup in the wound

• inner table of the skull may have indentation from pellets

Shot

• fx  skull, shreds brain, pressure waves increase the severity of wounds and eject brain tissue

gas

enters the closed head chamber, rapidly expands, skull fx to relieve pressure

contact SGW of trunk

• Less deformation than head wounds

• Impression from muzzle

• Chest and abdomen expand

• Loose contact: circular area of soot and gunpowder around the wound

• Cherry red discoloration

range of fire close range wounds

• gunpowder stipple

• it depends on type of powder used and the barrel length

• the stipple may be out to three feet

wounds produced by wads and shot cups

• Produce abrasions or petal marks adjacent to the entrance wound at ranges of 1-3 feet

• A wad or cup may enter the wound at close range

Range of fire close range wounds

• Stipple less than handgun at the same distance

• Wad and or cup may strike the body or be deposited in the wound

• Wad/cup injury: petal marks, petals may bend back at different distances

range of fire distant range

• entrance wound increases in size with distance

• by three feet: scalloped margins

four feet

main entrance surrounded by satellite woundssi

six to seven feet

cuff of satellite wounds

ten feet

great variation depending on ammo, choke and range

filler abrasions from shot

• White filler may surround shot

• can resemble gunpowder stipple

• very small particles are seen on skin or clothing

• usually white synthetic beads

range of fire distant range

• Weapons with the same choke may produce different patterns at the same range

• Different brands of ammo can produce different patterns in the same range

• you need to use the actual weapon and the same brand of ammo to obtain the most accurate results

shotgun slugs

• single projectile

• it may be encased in a sabot

• have various wads

• single large wound

• adjacent injuries may be from wads or sabots

miscellaneous issues

• “Sawed-off” shotgun: illegal when the barrel is less than 18 inches

• It is illegal because the shorter barrel makes the weapon easier to conceal

• Pellet spread does not change until the barrel is less than 9 inches long

• The uneven barrel muzzle may impart tool mark impressions on the exiting shot cup and may aid in the identification of the specific weapon