Internal Balistics Flashcards
What is ballistics?
The scientific study of the motion of projectiles
What are the Ballistic phases?
- Internal
- Intermediate
- External
- Terminal
What is Internal ballistics?
The scientific study of the operating process within the gun from the moment the propellant is ignited until the projectile leaves the barrel
What are the goals of ballistics?
- Launch the projectile safely
- launch the projectile with uniformity
- Achieve consistent muzzle velocity
What are some burning characteristics?
Propellant composition
- Burning Rate
- Pressure index
- Force constant
- Co volume
Propellant granule
- The ballistic size
- form function
What is Piobert’s law?
The surface of a burning propellant recedes layer by layer in a direction normal to the surface
What happens to the rate of burning of propellant if pressure is increased?
As pressure increases, the rate of burning increases
What are the 6 areas of distribution for energy when the gun is fired?
- Projectile
- Heat in the gas
- Gun recoil
- Engraving of the driving band/bore friction
- Unburnt charge and gases
- Heat in the gun
What is the effect for an increase in charge weight?
- Pressure increases
- All burn point moves back
- Muzzle velocity increases
For the same weight of charge, what is the effect for an increase in propellant size?
- surface area of the propellant decreases
- Burning rate is less
- Pressure does not build as quickly
- All burnt point moves forward
- Muzzle velocity decreases
What is the effect of using a multi tubular propellant on internal ballistics?
Peak pressure is decreased however the projectile still receives good energy levels
What is the effect on internal ballistics of using a projectile of normal weight but shorter and a larger diameter?
Same muzzle velocity but less pressure compared with a standard shot
Why does fall back occur?
- Mis-match driving band
- Dirt or fouling
- Insufficient ramming force
- Misaligned projectile
What is the consequence of a fall back?
- Round falls well short
- Round breaks up on exit
- In bore detonation
- Blackened round
What are some ballistic abnormalities and their description?
Occasion-to-occasion effect
-Muzzle velocity variation, no known cause but can occur from lot-to-lot
The cold gun effect
-Further range due to a cooler barrel
Order of fire
-The order in which charges are used
Ballistic hump
-High muzzle velocity due to a new barrell
