🔍 Gunshot Residue Distance Estimation Simulator

Contact & Near-Contact Wounds

The muzzle presses the skin, so combustion gases sear tissue directly.

• 0–2 cm: Muzzle-to-skin gap (true contact)
• Dense: Soot deposit (blackened wound margin)
• Common: Muzzle stamp (imprint of muzzle end)
• Frequent: Skin tearing (gas expansion under skin)

Searing and muzzle imprint

Hot propellant gases burn skin at the entry point.

Gas-driven splitting

Trapped gas can tear the skin into a stellate wound.

Diagnostic value

Contact wounds confirm distance without any measurement.

Close-Range Soot & Stippling

Soot settles on skin while unburned powder grains stipple around it.

• 0–30 cm: Typical range (soot-bearing zone)
• Grey–black: Soot color (wipes off with cloth)
• Dense ring: Stippling (tight around the hole)
• Circular: Pattern shape (perpendicular shot angle)

Soot vs. stippling

Soot is smoke residue; stippling is embedded powder grains.

Distance shrinks soot

Soot deposit fades and vanishes by roughly 30 centimeters.

Testing soot removal

Soot wipes away; true stippling is permanent tattooing.

Stippling Without Soot

Soot particles fall short, but powder grains still reach and mark skin.

• 30–100 cm: Typical range (stippling-only zone)
• Absent: Soot deposit (gases dissipate first)
• Widens: Stippling spread (with increasing distance)
• Sparser: Density (fewer grains reach skin)

Why soot disappears first

Soot particles are lighter and lose momentum sooner.

Powder grains persist

Denser unburned grains carry further before losing speed.

Pattern widening

The stippling ring grows wider as distance increases.

Distant Gunshot Wounds

Beyond about a meter, only the bullet itself reaches the skin.

• >100 cm: Typical range (residue-free zone)
• None: Soot (fully dissipated)
• None: Stippling (grains fall short)
• Abrasion ring: Wound margin (from bullet contact only)

Residue falls short

Gas, soot, and powder all lose energy before skin.

Abrasion collar

A thin ring of scraped skin still frames the hole.

Limits of the method

A clean wound only proves distance exceeds one meter.

Measuring the Pattern to Estimate Distance

Test-firing the same firearm builds a reference curve for comparison.

• Test-fire: Method (same gun, same ammo)
• Diameter match: Comparison (pattern vs. reference)
• ±several cm: Precision (depends on firearm)
• Range-of-fire: Use (key trial evidence)

Reference test-fires

Examiners fire the same weapon at known distances.

Diameter comparison

The wound pattern is matched against the reference series.

Courtroom relevance

Estimated distance can support or refute a suspect account.