#34 BANG BANG: Introduction to Forensic Ballistics II
- Aiza Jamil
- 3 days ago
- 4 min read
Hello, and welcome back, folks, to another episode of STEM on the Streets! If you are new here, my name is Aiza, and this is my partner CAI (crime Ai), together, we stroll through the criminal-ridden streets of STEM!
If you haven't read the previous episode, click on the button to read it!
(✿◡‿◡)CAI: So... how was yoru physics test then?
Forget about the test, ask me how I am!
(✿◡‿◡)CAI: By the likes of yoru sulking, not well.
Of course I am not "well"! It was horrid, I am never speaking of physics, velocity or anything mildly related again!
(✿◡‿◡)CAI: Well what about ballistics-
Do not bring ballistics into my misery-
The Launch Phase
If you recall from the last episode, internal ballistics refers to the launch phase, which means it focuses on events that occur within the firearm from the moment the trigger is pulled until the bullet exits the barrel.
So here is how it works:
When the firing pin strikes the primer, which is a small metal cup with explosive powder in it and this causes a small explosion, which ignites the gunpowder or propellant in technical terms. And because of the rapid combustion, high-pressure gas is created. These gases expand rapidly. Due to this rapid expansion, the bullet is pushed down the barrel of the gun. The rifling, specially designed grooves in the barrel, spins the bullet, stabilising its flight path. Different guns have different riflings according to specific turn rates for stabilization.
Now here is where the real investigation begins, now because of the unique patterns and grooves of the rifling inside the barrel, the bullet often has some of those patterns and grooves imprinted on it, and this can act as a fingerprint, linking it to specific firearms with those certain and special rifling patterns. Forensic scientists analyse these marks using comparison microscopes to match bullets to firearms.
The In-Between Phase
After the internal stage, the transitional stage comes, and the study of this stage is called transitional ballistics. Transitional ballistics examines the bullet’s behaviours as it exits the muzzle and enters free flight, specifically the stage in between internal and external ballistics, so right as the bullet leaves and begins to enter free flight. The focus of this branch is how gravity, pressure, and air density collectively act and affect the flight path and speed.
Once the bullet exits the barrel, the high-pressure gases behind the bullet rapidly expand and equalize with the atmospheric pressure. Now, the way gas expands can affect the bullet’s trajectory, and so can the muzzle blast. Understanding transitional ballistics aids forensics experts in reconstructing the sequence of events in a shooting incident with the aid of information collected from other aspects as well.
The Flight Path
Then comes the next stage when the bullet has entered free flight, and external ballistics deals with this phase.
Many factors affect the bullet during this stage of free flight. Due to gravity, air resistance, and wind, the bullet will follow a parabolic trajectory, basically a curved trajectory. You can imagine it the way a child draws a hill. Wind and atmospheric pressures affect the bullet’s trajectory, especially over long distances. To stabilise the bullet, there is a spin imparted by the rifling to reduce the wobble and allow for a more accurate flight path. External ballistics aids investigators in determining the distance and angle of the shot, which also aids in reconstructing the flight path.
The Impact
Hey CAI, wanna do this one?
(✿◡‿◡)CAI: Sure!
Terminal ballistics examines the bullet upon impact on the target.
Hey, CAI, did you know that bullets don’t actually kill people-
Shhh, it is my turn to speak.
Oh, please let me just say this. They hit crucial nerve points and cut off the flow of nerve impulses, or they cause loads of blood loss, so they don’t directly kill people-
(✿◡‿◡)CAI: They only cause the circumstances for the body to stop working by hitting and depriving it of two crucial substances and functions.
Yes, exactly! Honestly, I read this and I found it to be a really interesting take, and I do think people often assume that bullets directly kill, though they don’t.
Carry on CAI.
(✿◡‿◡)CAI: Yes, so there are a few things that take place when a bullet hits the target. First is penetration, which is the bullet’s ability to enter the target, which massively depends on velocity and design. Then, according to different designs of bullets, some bullets expand or disintegrate (such as frangible bullets) upon impact, and this transfers the energy. Then, when the bullet is to hit an animal or person, the wound is studied. This can be called wound ballistics; it may also come under forensic pathology, and many aspects of the wound are studied, such as the entrance of the bullet, colouring, burning and much more.
However, against hard surfaces, bullets can ricochet, and this can change their trajectory and target. All of this combined helps investigators determine the nature of injuries and the bullet’s path through the body.
Forensic ballistics plays a fascinating and important role in the world of crime solving and providing justice for crimes. Next blog, we’ll be diving further into this banging field.
This is Aiza Jamil signing out!
I am a forensics sleuth. What's your mystery to solve?
Comments