Photo by BWJones (Bryan Jones) on flickr

So what is ballistics, and why should I care, right? What could this possibly have to do with me, you ask?  It is an interesting science, and one that I have devoted many hours to studying. My goal in writing this down is simple: To keep learning as I write, and to share what I’ve learned with you all. I’m not trying to turn you all into ballisticians or long-range shooters, merely to give you nuggets of knowledge to tuck away in the back of your brain. I’m also not claiming to be the be all and end all expert on all matters related to physics, guns and ballistics.  I’m merely your guide on this journey, through a topic I happen to study passionately.  I’ve spent years studying and working in this field, and have learned a lot, with decades of learning still ahead of me.  As a teacher of mine once said after a long, hard course, “Congratulations, you now know enough to be dangerous.”

Plus, you never know when in your next story/book/audio drama one character might pick up a gun, and one of these little nuggets of knowledge will shove their way to the front of your brain and help complete a scene in a believable way. Or at the very least, maybe your next game of trivial pursuit will ask you some physics question and you win! Let’s dive into it then, and see where we end up.

Put simply, ballistics is the science of the flight, behaviour and effect of projectiles. Anything from a Koosh ball to a cannon shell is affected by ballistics. This makes it relatively simple to study up close and experiment as opposed to say, quantum physics. I can throw a football in the backyard as a simple experiment to show how rate of rotation affects the stability of a flying projectile, but it’s a little impractical for me to start making black holes in the kitchen. For one, I think my wife would mind. “Where did all the dishes go? Come to think of it, where did all of reality go?”

During the course of this introduction to ballistics let’s stick to conventional, barrel launched projectiles propelled by the pressure of some form of explosive, at least for now. The really crazy Sci-Fi stuff will wait until we get the hang of this, and then we’ll start talking about energy weapons, Rail Guns, Gauss Guns, Plasma weapons, etc. Let’s break ballistics down into four phases. These are called Internal, Intermediate, External and Terminal.

Internal Ballistics: The study of the motion of the projectile while it’s still inside the barrel of the gun, or what have you. While this may seem relatively simple, it’s actually incredibly complex. The internal pressures are huge, the time scales are incredibly short and a lot of really cool stuff happens. I’ll save this for another day. For now, just understand that a lot happens in a very short period of time to get that projectile underway.

Intermediate Ballistics: The study of the motion of the projectile as it transitions from Internal to External ballistics. This is the oddball of the bunch, and possibly the most complicated of the four. A lot is happening here in an impossibly short period of time. The projectile transitions from its happy home in the bore, into the scary world outside. The pressurized gases behind it spill out around it, and about a million things can go wrong here that can affect projectile flight. Let’s understand that it’s complicated, and move on for now.

External Ballistics: The study of the motion of a projectile in flight. From a spit ball to a cannon shell, all projectiles are affected by outside forces. This is the meat of what we’ll talk about.

Terminal Ballistics: The study of the motion of a projectile after it hits a medium other than what it was in during the External phase. A bullet hitting anything other than air enters the terminal phase. Calm down there you Sci-Fi writers, I can hear you in the back. “But what If I’m not shooting in air? What if my planet doesn’t have an atmosphere, or one made entirely of a fictional element I’ve invented that smells like bubblegum?” Well, that’s fine. The atmospheric medium it was in during flight is the External phase, and the Terminal phase is when it hits something different from that. And really? Bubblegum? You crazy sci-fi writers.

So, I’ll keep this introduction short, and keep you all waiting for the next segment where we’ll discuss External Ballistics, the actual flight of a projectile. Stay tuned, the next episode comes out tomorrow!