External Ballistics
Definition
Study of bullet flight from muzzle to target. Governed by gravity, air drag, wind, spin-stabilisation, Magnus effect and (at long range) Coriolis force.
- Scope
- Bullet flight from muzzle to target
- Forces
- Gravity, air drag, wind, Magnus effect
- Long-range factor
- Coriolis force
- Distinguished from
- Internal ballistics (in-barrel), terminal ballistics (impact)
Common questions
Why does spin-stabilisation matter for external ballistics?+
Rifling imparts spin that stabilises the bullet gyroscopically in flight, keeping it point-forward against air resistance; without that spin the bullet would tumble, lose accuracy rapidly, and behave unpredictably over distance.
When does Coriolis force become significant enough to matter in a trajectory calculation?+
It becomes practically relevant mainly at long range, roughly several hundred metres and beyond, where its small per-second deflection accumulates over the bullet's longer flight time; at typical handgun distances its effect is negligible.
Related terms
- Ballistic Coefficient (BC)
- The ratio of a projectile's sectional density to its drag relative to a reference standard (G1 or G7). Higher BC means less...
- Deflagration
- A subsonic combustion front propagating through an explosive by thermal conduction. Characteristic of low explosives such as black powder and smokeless powder;...
- Internal Ballistics
- Study of what happens inside the firearm from primer ignition to bullet exit at the muzzle. Includes propellant combustion, gas pressure, bullet...
- 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,...
- 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...
- Terminal Ballistics
- Study of bullet behaviour at the target. Includes penetration, permanent and temporary cavity, expansion or fragmentation, yaw and tumble, energy transfer.
- Wound Ballistics
- Sub-branch of terminal ballistics dealing with biological tissue. Entry wound with abrasion collar, wound track, exit wound, hydrostatic shock in fluid-filled organs.