I don’t know what she is charged with, but charges of negligence is the appropriate charge. It was her duty to prep the gun so that the gun did not represent a threat to anybody else.
It would be same kind of charge if you had the responsibility of strapping down some lumber and you didn’t take proper care to do so and your driver lost his load and it ended up killing somebody.
They are all charged the same. Its appropriate for all of them.
I drove interstate trucks for years. The driver is responsible for securing the load.