https://www.washingtonpost.com/news/morning-mix/wp/2014/08/1...
Full metal jackets are required for war, while law enforcement use bullets for stopping power.
One way the U.S. could reduce gun deaths would be to require full metal jacket ammunition; It decreases the likelihood of death for any given hit; (though increases ricochets and likelihood of stray bullets)(also increases price of every bullet sold)
That being said, there has been a lot of evidence that shows that HP rounds penetrate further than conventional wisdom would expect, and it likely gives LEOs a false sense of security when firing in an apartment complex or into crowds.