Officer Ryan Tuggle works at the sharp end of gun crime, patrolling the streets of Denver at night when armed gangs exploit the cover of darkness.
In the United States, every year more than 13 ,000 people are killed by guns.
That figure doesn't include armed robberies.
With so many guns around, keeping the peace makes a police officer's job extremely challenging.
For the third part of his special series on America's gun culture, our correspondent Jon Brain has spent the night on patrol with police in Denver, Colorado.