"They" and "their customers" are the same folk.
The users--The FBI folks at Quantico and their law enforcement partners--do not have any reason for not wanting to see
anything. They are looking for the best possible answers.
People in the ammunition industry perform their tests using the exact same protocols defined by those to whom you refer to as "their customers".
They are not perfect, but nothing can be. There are too many variables in real-life shootings.
Ammunition specifications are based on based on things:
- What medical experts say the projectiles must do.
- Testing using ballistic gel as a surrogate for the human body.
- Extensive shooting exercises, to determine which gun and load combinations provide the best probability of performing in the field as part of a person-machine system.
How might that be?