Choke (Shotgun)
Definition
Constriction at the muzzle of a shotgun barrel that controls pellet spread. From most-open to most-tight: cylinder, improved cylinder, modified, full choke.
- Location
- Muzzle of shotgun barrel
- Function
- Controls pellet spread
- Order, open to tight
- Cylinder, improved cylinder, modified, full
- Relevance
- Range-of-fire estimation from pellet pattern
Common questions
How does choke affect a forensic range-of-fire estimate?+
A tighter choke keeps the pellet pattern narrower for a given distance than an open choke, so an examiner must know or test-fire the specific gun's choke before using pellet spread diameter to estimate the shooter's distance from the target.
Why would an examiner need to test-fire the actual weapon rather than use published choke tables?+
Published spread figures are averages for a nominal choke setting, but actual pattern spread varies with ammunition type, barrel wear, and the individual gun, so a reconstruction that relies on distance estimation should be validated by test-firing the same gun and comparable ammunition when available.
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.
- 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...
- Permanent Cavity
- The lasting wound channel produced by the bullet's direct crushing and laceration of tissue. Diameter approximates expanded projectile diameter. At handgun velocities,...
- Ricochet
- The deflection of a bullet off a surface at a low angle of incidence, producing a new trajectory that diverges from the...
- Temporary Cavity
- The transient radial tissue displacement produced by a bullet's passing. Caused by the transfer of kinetic energy to surrounding tissue via compression...