One good source might be NIST. Here’s an open access ballistics dataset: https://www.nist.gov/programs-projects/nist-ballistics-toolm...
Edit: I should have looked at the linked book first, since this dataset is listed in Ch3. Oops.
Edit: I should have looked at the linked book first, since this dataset is listed in Ch3. Oops.
I don't know of any resources where data that has been extracted from some crime scene(s) can be downloaded.
How could one build on their knowledge after going through this resource if they would like to?