Jury Duty, Part 7: Ballistic Microscopy

In which a witness is grilled on her expertise and shuts down the defense lawyers

Today an expert in ballistics was called to be a witness for the DA. So far she was the most interesting witness, because she was really smart.

Because there were more casings than bullets recovered in this crime, a lot of time was spent covering how she was able to determine that two guns were used in this crime: a 9mm semiautomatic, most likely a Fabrique Nationale or a Smith & Wesson, and an Uzi type pistol.

An Uzi. Still marveling at this fact.

Of the several recovered bullets (1 from a fence post and the rest from the bodies of the victims), all of them were fired from either of these two guns, although there are about half as many bullets as there are casings.

I learned a lot from her*, but a few of the most interesting things that came up today were:

  • She can use the patterns of scratches and dents that the ejection of a casing makes to match the type of gun that fired the cartridge
  • She can determine what sort of gun fired what a based on the impression the pin makes and the sort of markings that are created as the bullet is loaded into the chamber
  • There were 2 intact cartridges recovered on the street about a block from the crime that were completely unrelated to this crime. Someone lost two live .223 cartridges on the road and never even noticed! Yay Oakland!

The defense lawyers were pretty hard on her, but I’m guessing she had training in testifying in court and handled it very well.

Ballistic forensics sounds like a pretty interesting field, though anything involves an electron microscope and getting to fire automatic weapons into jello sounds like it would probably be interesting.

*To be clear, I don’t watch a ton of crime shows, and even the ones I do, I figured they embellished most of the facts; you know, like CSI can “enchance” a tiny pixelated piece of shit picture it is suddenly a stunning 4k masterpiece.


The Jury Duty Saga