An interesting forensic ballistics article

Something I had no heard of - standard fired cases for calibration.

Interesting articlde. Thanks!

On a related area, I recently learned that at least some forensic labs in Europe have special unheadstamped 9mmP cartridges, and I assume other calibers, that are used to test fire guns to take sample case head impressions. Headstamps can apparently sometimes prevent capture of critical elements of the impression and the arguement I have heard is that the unheadstamped case provides a better image for comparision with crime scene cases.

has anyone heard of this approach being used in US labs?