Entrance Bevelling
Definition
The widening of a bullet-penetration hole toward the exit side, analogous to bevelling in bone wounds; the narrower opening is on the impact face and the wider opening is on the far face.
- Location
- Impact face of a bullet penetration hole
- Shape
- Narrower opening at impact, widening toward exit
- Analogous to
- Internal bevelling in bone gunshot wounds
Common questions
How is entrance bevelling used to determine the direction a projectile travelled?+
Because the hole widens toward the exit side and stays narrow at the impact face, examining the cone shape of the fracture in glass or bone lets an examiner state which side the projectile came from, even without recovering the projectile itself.
Can entrance bevelling alone establish the shooter's distance or angle?+
No. It establishes direction of travel through the material, not range. Distance and angle need separate indicators, such as stippling patterns, wound morphology, or trajectory reconstruction using multiple defects.
Related terms
- 3R Rule
- The fracture-analysis mnemonic: Radial cracks form at Right angles to the Reverse (far, non-impact) side of the glass. Applied to the fracture...
- Bayesian Likelihood Ratio (LR)
- The statistical framework that evaluates glass-fragment evidence by comparing the probability of the observed fragment population assuming contact with the source glass...
- Concentric Cracks
- Approximately circular cracks centred on the impact point; they form second, on the near (impact) face, and terminate when they encounter pre-existing...
- Cone Fracture
- A conical crack produced by concentrated contact loading (Hertzian contact), opening on the far (exit) face of the glass; the cone geometry...
- Fracture Termination Rule
- The principle that a propagating crack terminates when it encounters a free surface created by a pre-existing crack; at any T-junction, the...
- Hackle Marks
- Ridges on the fracture surface oriented perpendicular to the crack propagation direction; they appear in the mist and hackle zones at higher...
- Mirror Region
- The smooth, flat area of a fracture surface nearest the crack origin, where the crack was propagating slowly and stably before accelerating...
- Mist Region
- The transitional fracture surface zone between the smooth mirror region and the rough hackle region, where the crack begins to bifurcate at...
- Radial Cracks
- Cracks extending outward from an impact point in approximately straight lines, like spokes on a wheel; they form first, on the rear...
- Secondary Transfer
- The movement of a glass fragment from a primary surface (which contacted the broken glass) to a secondary surface (which contacted the...
- Wallner Lines
- Rib-shaped features on a glass fracture surface produced by the interaction of the propagating crack front with reflected elastic stress waves; their...