Near-Zero Crossing
Definition
The shorter of the two distances at which the bullet's trajectory intersects the line of sight. For a rifle zeroed at 300 m, the near-zero crossing is typically around 25-30 m.
- Field
- External ballistics, trajectory analysis
- Definition
- Shorter of two sight-line trajectory intersections
- Example
- About 25-30 m for a rifle zeroed at 300 m
Common questions
Why does a zeroed rifle cross the line of sight twice rather than once?+
The bullet's path rises above the line of sight shortly after leaving the barrel because the sights are angled slightly downward relative to the bore, then arcs back down under gravity, crossing the sight line once on the way up (near-zero) and again at the intended zero distance (far-zero).
Why does near-zero crossing distance matter to a shooting reconstruction?+
Knowing where the bullet path sits relative to the sight line at a given range helps a reconstruction expert estimate point of aim versus point of impact, which feeds into determining plausible shooter position and distance in a scene where the exact zero setting of the weapon is known or can be tested.
Related terms
- Ballistic Solver
- Software (JBM Ballistics, Strelok Pro, Hornady 4DOF, AB Quantum) that computes trajectory accounting for drag, BC, muzzle velocity, and atmospheric conditions. Supplementary...
- Battle-Sight Zero (BZO)
- The zero range selected by a military or paramilitary organisation as the standard setting for field use. US Army M4: 300 m....
- Bore Axis
- The centreline of the barrel through which the bullet travels. The starting reference line for measuring gravity drop and the elevation difference...
- Gravity Drop
- The vertical distance a bullet falls below the bore axis at a given horizontal range, accumulating continuously from the instant of muzzle...
- Point-Blank Range (PBR)
- The maximum distance at which the bullet stays within the vital-zone radius above or below the line of aim without the shooter...
- Trajectory Rod
- A rigid fibreglass or aluminium rod inserted through a bullet wound channel and aligned with the channel geometry to define the bullet's...
- Vital Zone
- The defined target area used to compute point-blank range. For human thorax: typically 20 cm diameter (10 cm radius) centred on the...
- Zero Range
- The horizontal distance at which the bullet's trajectory crosses the line of sight. At this range, the point of aim and point...