Firearm Wounds
Understanding lethality
Summary Table
| Factor | Effect on Lethality |
|---|---|
| Placement | Primary determinant (CNS & heart = most lethal) |
| Caliber | Larger = more trauma; small calibers still deadly |
| Muzzle Energy | More energy = deeper, wider wound |
| Velocity | Higher = more penetration and cavitation |
Shot Placement (Most Critical Factor)
"Where the bullet goes" is more important than what type of bullet it is.
- Central Nervous System (CNS): Hits to the brainstem or spinal cord typically cause instant death or incapacitation.
- Heart & Great Vessels: Shots to the heart or aorta lead to rapid internal bleeding and cardiac arrest.
- Lungs: Often survivable with medical care, but can lead to complications like pneumothorax.
- Abdomen: Organ damage may be fatal if major arteries are involved, but not always immediately lethal.
- Extremities: Usually non-lethal unless major arteries are hit or shock/infection occurs.
Caliber (Bullet Diameter and Mass)
Larger calibers generally cause more tissue destruction, but lethality still depends on shot placement.
- .22 LR: Small but lethal, especially to the head.
- 9mm / .38 / .45 ACP: Common calibers with varying expansion and penetration capabilities.
- Rifle Rounds (.223 / .308): High-velocity, often causes cavitation and fragmentation.
- Shotgun (12 gauge): Extremely destructive at close range.
Muzzle Energy (ft-lbs or Joules)
Higher muzzle energy = more potential for deep and wide tissue damage.
Formula: Energy = (1/2)mv²
- .22 LR: ~100 ft-lbs
- 9mm: ~350 ft-lbs
- .308 rifle: ~2,500 ft-lbs
- 12 gauge slug: ~2,800 ft-lbs
High-energy rounds can create temporary cavitation, damaging tissue beyond the direct bullet path.
Velocity (Feet per Second - FPS)
Velocity affects both penetration and cavitation.
- Handguns: ~700–1,300 fps
- Rifles: ~2,200–3,000+ fps
High-velocity projectiles can shatter bone and create significant hydraulic shock.
Temporary vs. Permanent Wound Cavity:
- Low velocity = smaller, direct damage path
- High velocity = large cavitation, wider tissue trauma
Additional Considerations
- Bullet Type: Hollow points expand, FMJ penetrate, fragmenting bullets increase internal trauma.
- Barriers: Clothing, walls, and body armor affect bullet behavior.
- Multiple Shots: Increase probability of hitting vital organs and accelerating fatality.