Podcast
Questions and Answers
Which of the following best describes the focus of internal ballistics?
Which of the following best describes the focus of internal ballistics?
Internal ballistics is concerned with the projectile's movement after it exits the firearm.
Internal ballistics is concerned with the projectile's movement after it exits the firearm.
False
What term is used to describe the study of the projectile's interactions as it moves through the medium?
What term is used to describe the study of the projectile's interactions as it moves through the medium?
external ballistics
The study of _______ ballistics includes the effects and interactions of the projectile at the target.
The study of _______ ballistics includes the effects and interactions of the projectile at the target.
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Match the type of ballistics with its description:
Match the type of ballistics with its description:
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What is the primary focus of wound ballistics?
What is the primary focus of wound ballistics?
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The projectile is unaffected by the gases produced from the propellant.
The projectile is unaffected by the gases produced from the propellant.
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What begins the time period under study in wound ballistics?
What begins the time period under study in wound ballistics?
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The interaction of a projectile with living tissue is studied to understand its effects on __________.
The interaction of a projectile with living tissue is studied to understand its effects on __________.
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Match the following terms with their correct descriptions:
Match the following terms with their correct descriptions:
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What is the term used to describe the rate at which a propellant granule reduces in size?
What is the term used to describe the rate at which a propellant granule reduces in size?
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For modern propellants, the Pressure Index is always less than 1.
For modern propellants, the Pressure Index is always less than 1.
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What is the requirement for calculating the Force Constant of a propellant?
What is the requirement for calculating the Force Constant of a propellant?
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The rate of a burning propellant at 0.1 MPa pressure is called the __________.
The rate of a burning propellant at 0.1 MPa pressure is called the __________.
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Match the following characteristics with their definitions:
Match the following characteristics with their definitions:
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Which of the following accurately describes the behavior of granules during the burning process?
Which of the following accurately describes the behavior of granules during the burning process?
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A granule's Ballistic Size is defined as the longest distance between any two opposing surfaces.
A granule's Ballistic Size is defined as the longest distance between any two opposing surfaces.
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What is the common burning rate of modern propellants in mm/sec/MPa?
What is the common burning rate of modern propellants in mm/sec/MPa?
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What shape of propellant granule has a positive form function coefficient?
What shape of propellant granule has a positive form function coefficient?
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Degressive propellants increase burning surface from both inner and outer surfaces.
Degressive propellants increase burning surface from both inner and outer surfaces.
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What is obtained when pressure reaches atmospheric level after a firing sequence?
What is obtained when pressure reaches atmospheric level after a firing sequence?
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The __________ provides spin to the projectile during firing.
The __________ provides spin to the projectile during firing.
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Match the type of propellant with their characteristics:
Match the type of propellant with their characteristics:
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What is the shot start pressure?
What is the shot start pressure?
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The shape of the projectile has no effect on the shot start pressure.
The shape of the projectile has no effect on the shot start pressure.
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What is the impact of high projectile mass on acceleration?
What is the impact of high projectile mass on acceleration?
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The __________ curve illustrates the pressure and volume changes during the firing sequence.
The __________ curve illustrates the pressure and volume changes during the firing sequence.
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Match the propellant type with its flame temperature:
Match the propellant type with its flame temperature:
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Which of the following factors affects internal ballistics?
Which of the following factors affects internal ballistics?
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Higher average pressure is associated with progressive propellants.
Higher average pressure is associated with progressive propellants.
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What occurs at the all burnt point (ABP)?
What occurs at the all burnt point (ABP)?
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The __________ is the radial expansion of the cartridge case.
The __________ is the radial expansion of the cartridge case.
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Study Notes
Internal Ballistics
- Internal ballistics is the study of the motion of a projectile within the firearm barrel
- The aim of the study is to acquaint the class with internal ballistics
- The preview shows three main parts: Ballistics Terminology, Propellants, and Firing Sequence
Ballistic Terminology
- Internal ballistics studies the interaction between the projectile and the target (TGT)
- Intermediate ballistics is a study of events occurring between projectile initiation and its interaction with the target
- Terminal ballistics is the study of events occurring between projectile–target interaction and projectile's exit
- Wound ballistics studies the interactions between a projectile and living tissue
- Ballistics studies the motion of projectiles—their propulsion, free flight, and impact
Propellants
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Propellants are crucial for producing consistent muzzle velocity
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Burning characteristics are determined by chemical composition, granule design (like size), and experimental observation (Piobert's Law)
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Chemical composition includes burn rate constancy, pressure, force, and co-volume
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Granule design parameters include ballistic size
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Piobert's Law states that all surfaces recede at an identical rate, and propellant granules burn in layers, retaining their original shape
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Burning rate constant refers to the rate at which a granule reduces in size at a pressure of 0.1 MPa
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This rate is affected by the propellant's initial temperature:
- Black powder has a typical burning rate constant of 18 mm/second/MPa;
- Smokeless powders have a burning rate constant ranging from 0.5 to 3 mm/second/MPa
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Pressure index is the coefficient relating burning rate changes to pressure changes (For modern propellants, Pressure Index ≈ 1)
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Force constant refers to the energy released during propellant burning (propulsive power)
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It's measured by burning a specific propellant amount in a closed vessel; Double and triple-base propellants differ from single-base propellants.
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Co-volume is crucial for calculating force constant - exact volume of closed vessel of interest needed (also known as a closed volume)
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Granule design includes ballistic size (e.g., web size), which can impact burning process
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Different propellant shapes include ball, flattened ball, ball & stick, flake, single perf, 7-perf and 19-perf
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Form function coefficient measures the geometric relationship between the fraction of propellant burned and the ballistic size at any given moment (for various granule shapes)
Firing Sequence and Factors
- Firing sequence starts with striking the primer cap, leading to flash, and igniting the propellant
- Oburation refers to the radial expansion of the cartridge case that seals off the rearward escape of gases
- Shot start pressure is the point where the bullet is released/disengaged from the cartridge case and begins its motion through the barrel.
- Rifling refers to grooves machined in the barrel to provide spin to the projectile (controlled by twist rate and pitch)
- Set up means fitting the bullet between lands and grooves inside the barrel, preventing gas escape and enhancing projectile stability. This process also involves setting up the bullet in rifled barrel grooves.
- Firing sequence involves propellant ignition, obturation, shot start, bullet movement, rate of gas production, peak pressure and a pressure-time curve
- All-burnt point (ABP) is the time when all the propellant has been burned (happens after 1 millisecond in pistols, longer in artillery)
- Peak pressure is determined by rapid gas release, total burning surface, high force constant, high projectile mass, and restricted gas expansion volume; inertia interferes with acceleration
Operating Forces
- Propelling force is calculated using propellant gas pressure, surface area of the projectile's base
- Other operational forces include frictional forces and the projectile's mass
- Overall acceleration depends simultaneously on propellant characteristics and frictional forces
Factors Affecting Internal Ballistics
- Factors affecting internal ballistics include propellant energy, propellant charge quantity and weight, type of propellant and grain shape, charge temperature, dimensions/space where charge is enclosed, barrel length, caliber, and temperature, projectile mass, projectile material and shape, and the material of the cartridge case, erosion
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Description
Test your knowledge on internal ballistics, including projectile interactions, propellant behavior, and their effects on living tissue. This quiz will challenge your understanding of key concepts in ballistics and their practical applications.