Ballistics simplified

Last month, I wrote about the importance of real world experience in writing sensorial details and included the example of firing a gun. I discussed this (and a scene from my WIP) with a friend who also happens to be an expert in ballistics. The discussion gave me some interesting insights I thought I’d share with you all.

Not having being shot or fired upon myself (thank God!), I asked him how I might learn a little more about the myths vs facts on this topic. Specifically, do bullet proof vests really protect the wearer from injury as well as death? Would the damage from a Desert Eagle .50 AE be different from a Glock 19 9mm? And would my hero be disabled if he caught a bullet at close range? The answers were enlightening. I’m going to try and take out the technical jargon and summarise what I learned.

Back face deformation example, soft body armor. The standard for a material to be considered bullet proof is back face deformation of no more than 44mm or 1.73in (that dent is digging into your rib cage — ouch!).

The level of injury all comes down to something called “back face deformation”. When the bullet impacts the vest, it will make a dent in the vest. This dent pushes against whatever is behind the vest (eg, stomach, ribcage). See the picture to the right. This deformation will be more significant for a soft bullet proof vest (eg, standard issue police). It will be different for a ceramic or other hard body armor (eg, what SWAT or the military use), although both should protect from stab wounds. It will also depend on the firearm.

You can watch these YouTube videos for more examples:

What does this mean for the wearer in reality? Most people who are shot will fall over from shock rather than impact. It will hurt a lot. There is almost certainly going to be a broken rib or two.

If you don’t mind seeing real life injuries (Trigger Warning), here is a real life example of a man (in a selfless act of public service) who decided to test it out on himself. I am told the only reason he didn’t break a rib was because the hit was below the ribcage.

If you have any questions about this, feel free to ask in the comments below or via my Twitter, and I will try and get you an answer.