Firearms and ammunition for the doctor
- Topic
The type of weapon and ammunition changes the wound: knowing this helps you describe it well and avoid conclusions the findings do not support.
What it is
This topic explains, for educational purposes only, how the type of weapon and ammunition changes what the doctor sees on the body. Rifled weapons (pistols, revolvers, rifles) fire a single projectile that the grooves of the barrel set spinning and mark in their own way. Smooth-bore weapons (shotguns) usually fire many pellets that spread with distance. The projectile's velocity and construction (lead, jacketed or expanding) decide how much tissue is damaged. There are also weapons that do not fire a conventional projectile, such as air guns, blank-firing guns and captive-bolt pistols, and all of them can cause serious injury or death. Range of fire and entry and exit wounds have their own pages.
Key facts
- Calibre states the inner diameter of the barrel; shotguns use another system in which a higher number means a narrower barrel.
- The size of the skin hole does not give the calibre exactly: skin is elastic and the hole may be smaller than the projectile.
- A jacketed (metal-cased) projectile tends to pass through the body; an expanding one deforms, gives up more energy and usually stays inside.
- The metal jacket can separate from the core: the radiograph may show separate fragments, and all of them must be recovered.
- A projectile that ricocheted or passed through another object before entering makes atypical, irregular and sometimes large holes.
- Improvised or modified weapons produce atypical patterns: the description must be objective, and interpreting the weapon is for the firearms laboratory.
Structure
- Cartridge for a rifled weapon: case, primer, propellant powder and projectile.
- Shotgun cartridge: case, primer, powder, separating wad and pellets (or a single slug).
- Blank cartridge: has primer and powder but no projectile; the gases and powder grains leave at high speed.
- Air gun: drives a pellet or small shot without powder, so it leaves no combustion residue.
Function
- Damage depends on the energy the projectile gives up to the tissue, not on its velocity alone: its mass, shape, deformation and whether it exits or stays all matter.
- Dense, inelastic organs (liver, brain) are damaged more by the temporary cavity than elastic ones (lung, muscle).
- Bone can shatter, and its fragments act as secondary projectiles.
Weapon types and what is usually seen on the body
| Type | What it fires | Typical feature on the body |
|---|---|---|
| Rifled bore (pistol, revolver, rifle) | A single spinning projectile | Entry wound with an abrasion ring; with a rifle, major internal destruction |
| Smooth bore (shotgun) | Pellets or a single slug | One central hole or many holes depending on range; wad at close range |
| Air gun | A pellet without powder | Small hole, no powder residue; the pellet usually stays inside |
| Blank-firing gun | Gases and powder grains, no projectile | Gas injury at contact or very close range, with burning and powder |
| Captive bolt | A bolt that goes in and retracts | Round hole, almost always frontal and midline, no projectile |
Next step: what to do and document
- Describe each hole separately (site, shape, measurements, edges, rings and residues) without stating the type of weapon or the calibre.
- Request radiographs before the autopsy or surgery to locate projectiles, pellets, wads and jacket fragments.
- Recover projectiles without metal forceps, so as not to create new marks, and package them labelled under chain of custody.
- Protect the deceased's hands with paper bags and keep the clothing, which may carry gunshot residue.
- In a living patient, record the injuries in detail in the medical record and inform the competent authority under the duty to report.
Test yourself
Think of the answer, then tap the question to see it.
What is the basic difference between a rifled and a smooth-bore weapon?
The rifled one fires a single projectile that the grooves set spinning and mark; the smooth-bore one (shotgun) usually fires pellets that spread with distance.
Why can a rifle bullet injure organs away from the visible track?
Because at high velocity it gives up a lot of energy and creates a temporary cavity that stretches and tears the tissue around the track.
What is found in a captive-bolt pistol wound?
A round hole, almost always frontal and midline, with bone fragments pushed inwards and no projectile, because the bolt retracts.
Can a blank-firing gun cause a fatal injury?
Yes. Although it fires no projectile, the gases and powder grains at contact or very close range can penetrate the skin and the skull.
Elsewhere in DurgiPedia
Connections
Educational content on forensic and legal medicine; not legal advice and no substitute for the technical guides of Colombia's National Institute of Legal Medicine and Forensic Sciences. Laws change: each page links the official text and says when it was last checked. For a real case, follow the guide in force and ask the competent authority.
Sources: Gunshot Wound Patterns: A Narrative Review From a Forensic Medical Perspective (Cureus, PubMed Central, 2026); Penetrating brain injury from captive-bolt guns: A retrospective multicenter study of 77 cases (Brain and Spine, PubMed Central, 2026); Carotid artery injury from an airgun pellet: a case report and review of the literature (Head & Face Medicine, PubMed Central, 2009); Nothing but hot air?-On the molecular ballistic analysis of backspatter generated by and the hazard potential of blank guns (International Journal of Legal Medicine, PubMed Central, 2021); Injuries from blank cartridge shots in suicide attempts within the South Korean military: a case series of five patients (Journal of Trauma and Injury, PubMed Central, 2024).
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Representative model, for educational purposes only.