Ricochet
Definition
The deflection of a bullet off a surface at a low angle of incidence, producing a new trajectory that diverges from the original. The outgoing angle is generally less than the incoming angle on hard surfaces, but varies with surface material.
- Typical critical angle
- Under 15 degrees on hard surfaces
- Angle relationship
- Outgoing angle is less than incoming angle on hard surfaces
- Surface dependency
- Deflection varies with surface material and hardness
Common questions
What happens when a bullet ricochets?+
A bullet bounces off a hard surface and changes direction. The new path doesn't mirror the incoming angle. Instead, the outgoing angle is generally less than the incoming angle, so the deflected bullet doesn't travel as far away from the surface as it approached.
At what angle does ricochet happen?+
Ricochet typically occurs when a bullet hits a hard surface at a glancing angle, usually under 15 degrees. The shallower the angle, the more likely deflection occurs. If the angle is too steep, the bullet tends to embed or deform instead of bouncing.
Why is ricochet important in crime scenes?+
Investigators use ricochet behavior to trace bullet paths and reconstruct what happened. Understanding how surfaces deflect projectiles helps determine where a shot came from and how the bullet traveled after impact, which is critical for scene analysis.
Related terms
- Accidental Discharge
- Unintended firing of a weapon without a deliberate trigger pull, usually caused by mechanical defect, sear wear, drop impact or unsafe handling.
- Angle of Impact
- The angle between the bullet's trajectory and the surface it penetrates, measured from the surface plane. Calculated from entry-hole geometry: sin(angle) =...
- Bullet Trajectory Kit (BTK)
- A laser-based trajectory projection system by Sirchie that replaces the physical rod with a laser module, projecting a visible beam along the...
- Bullet Wipe (Metal Wipe)
- The grey-black ring of bullet-jacket material (grease, metal oxides, carbon) deposited around the margin of an entry hole as the bullet's periphery...
- Burke and Rowe 1992
- The primary peer-reviewed study of bullet ricochet behaviour on concrete, asphalt, and vehicle metal surfaces, published in the Journal of the Forensic...
- Choke (Shotgun)
- Constriction at the muzzle of a shotgun barrel that controls pellet spread. From most-open to most-tight: cylinder, improved cylinder, modified, full choke.
- Faro Focus 3D
- A terrestrial laser scanner used for crime-scene documentation, capturing a full-resolution point-cloud model of the scene at millimetre accuracy. Trajectory rods or...
- Keyhole Wound
- An asymmetric teardrop-shaped bullet entry hole produced when the bullet strikes the surface sideways or is unstabilised, indicating close-range fire (pre-stabilisation) or...
- Kinetic Energy
- KE = (1/2) m v squared, where m is projectile mass and v is velocity. Doubling velocity quadruples the kinetic energy delivered...
- MOA (Minute of Angle)
- 1/60 of a degree of arc. Equal to approximately 2.908 cm (1.047 inches) at 100 m. Used in civilian and some law...
- Muzzle Velocity
- Speed of the projectile at the instant it leaves the barrel, expressed in metres per second (m/s) or feet per second (fps)....
- Ordnance Gelatin
- Calibrated tissue simulant. 10 per cent gelatin at 4 degrees C is the NATO and FBI standard; 20 per cent gelatin is...
Explained in these topics
- Bullet Trajectory Analysis, Ricochet and Scene ReconstructionThe deflection of a bullet off a surface at a low angle of incidence, producing a new trajectory that diverges from the original. The outgoing angle is general...
- Velocity, Penetration, Dispersion, Ricochet and Accidental DischargeDeflection of a projectile off a surface struck at a glancing angle. Critical angle for hard surfaces is typically under 15 degrees; angle of departure does no...