Intro to ballistics Flashcards
study of the motion of the projectiles.
Ballistics
greek word Ballo or Ballein which means
to throw
Roman war machine Ballista,
gigantic bow or catapult
systematized body of knowledge.
Science
refers to the bullet/slug/ball/pellet/flechette that passes through the barrel of FA.
Projectile
is the science of firearms identification by means of the ammunition fired through them.
Forensic Ballistics
as applied to ballistics or to any other subjects suggests a relationship to a court of justice and legal proceedings
Forensic
Derived from the Latin word Forensis which means_______that means “a public/market place, wherein people gathered for discussion of a subject in issue.
Forum
movement of projectile inside and outside barrel.
Motion
Kinds of Motion:
- Direct motion
- Rotary motion
- Translational motion
the forward movement of projectile with the action of expansive force of gases.
Direct motion
the turning of bullet inside and outside barrel with the action of the rifling
Rotary motion
the movement of projectile after hitting the target.
Translational motion
Interior Ballistics
- Also called Internal Ballistics
- Study of projectile while still inside the barrel
- From Breech to the Muzzle of barrel
Processes included in the study of Interior Ballistics:
- Firing pin hits the primer
- Ignition of priming mixture
- Combustion of gun powder
- Expansion of the heated gas in the chamber
- Pressure will be developed (pounds per square inch)
- Energy generated (foot pound)
- Recoil of the firearm
- Velocity of bullet inside the barrel (feet per second)
- Rotating of the bullet inside the barrel.
- Engraving of the cylindrical surface of bullet
Defects in FA that cause Misfire:
- Broken firing pin
- Loose firing pin
- Lacking length in firing pin (especially homemade guns)
failure of cartridge to explode
Misfire
Probable defects in the contents of Primer Cup
- Wet priming mixture
- Anvil is not properly fixed (slanting position)
- No vent or flash hole (factory defect)
- No priming mixture (factory defect)
is the delay of explosion
Hangfire
Combustion of gunpowder
A.Primer crushed the priming mixture against the anvil
B.Ignition of priming mixture and primer flash
C.Enters the vent or canal
D.Primer flash ignites the gunpowder and combustion happens.
Note:
- If priming mixture is defective, no explosion.
- If priming mixture is live and gunpowder is defective or wet, only the priming mixture will explode. This results to slow exit of bullet in the barrel or stock-up. Backfire & Barrel Breakage may happen if there is stock-up.
- To propel the bullet, priming mixture and gunpowder must explode simultaneously.
Individual Characteristics found in the Chamber:
Irregularities
Scratches
Roughness
imperfection
created during manufacture such as spiral cutting of the grooves
Irregularities
caused by tools used in the manufacture of the chamber.
Scratches