Tuesday, January 22, 2013

Every other TV drama is a cop show, so odds are good you'll have to write a cop episode sooner or later. But what's the difference between blood spatter and blood splatter? What's a hesitation wound? What are Galton details?

FORENSIC SPEAK is your basic primer of basic crime scene terms, from guns to toxicology to gas chromatography to fingerprinting to courtroom testimony. If you're a crime drama fan, you have certainly heard these terms used, but this book will tell you what they mean. It doesn't go into much depth, and there are a few places where I doubt the writer's expertise. (Rifling does not add "speed and range" to a bullet. It decreases both. It increases accuracy.)

But if you don't know the difference between a contusion and a laceration, the book may be a good read, and then you can read the Wikipedia articles on the subjects for more detail. And it may be particularly useful as you write scenes full of forensic babble...

 ... but remember, please, try to stage those scenes as arguments. Not only are arguments more fun; for some reason it is always easier to follow an argument than a diatribe.

11:35 PM

4 Comments:

Alex,

Thanks for the review! I really appreciate it! Great blog! Keep up the good work!

Just to clarify for your readers...

You're right that rifling does provide some resistance to the travel of the bullet. However, compared to a non-rifled barrel (like a musket or guns in the Victorian era), rifling actually aids in getting the bullet to travel faster, longer, and straighter.

Rifling's sole purpose is to cause "GYROSCOPIC" spin which keeps the bullet from yaw, pitch, wobble or any other variation in position along its intended trajectory. Stabilizing the bullet definitely increases accuracy compared to a bullet fired from a non-rifled weapon.

In other words... rifling keeps the bullet stable in the air the bullet is faster than a non-rifled bullet the farther they both travel away from the muzzle.

All things being equal, the rifled bullet travels farther and after certain distance is traveling faster than its non-rifled counterpart.

Here's an fun URL that describes the kinetics and ballistics still another way:
http://io9.com/5944455/the-physics-of-bullets-why-a-modern-gun-shoots-10-times-further-than-its-19th-century-counterpart

By  Unknown, at 5:21 PM  

I'm not following your physics. Yes, of course rifling increases accuracy. That's the whole point.

And, of course, modern rifled guns have a higher muzzle velocity than muskets. The bullet in a musket is much smaller than the barrel, leading to immense loss of power as the explosive gasses can escape without pushing the bullet out.

However, if you compare equivalent smoothbore guns, then some of the power of the bullet is spent on torque, through friction. That reduces velocity.

Certainly, out of a smoothbore gun, you will experience some wobble in flight. But wobble doesn't affect raw distance. What affects distance is velocity, angle, and air resistance. Are you claiming that a spinning bullet experiences less air resistance?

How does rifling increase range?

By  Alex Epstein, at 5:44 PM  

Note that modern smoothbore tank guns achieve greater velocity by using fins on their projectile, rather than rifling, precisely because smoothbore guns achieve higher muzzle velocity, hence greater range.

http://en.wikipedia.org/wiki/Rifling

By  Alex Epstein, at 5:47 PM  

Oh, Jennifer. You had no idea that Alex was such a military wonk. (No matter where we go, he figures out the best position to defend against a frontal assault.)

I looked at your book and it's excellent. Congrats.

By  Unknown, at 12:36 AM  

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