From Handwaving Freakoutery:

AR-15 murders are somewhere between “Death By Bucket” and “Death By Lawnmower” in the United States. They’re a little bit more common than getting struck by lightning, a little over half as common as “Death By Bees,” and less than a tenth as likely as “Death By Falling Out Of Bed.” Over twice as many people kill themselves during masturbation as die from AR-15 murders, and triple the number of people die by hitting errant deer with their cars at night as are murdered by AR-15. Feel free to check the sources, they’re in the graph. I have never yet heard a politician claim we were experiencing an Epidemic of Death By Lawnmower.

There were 24.4 million MSRs / “Assault Weapons” in circulation in 2020, and 60 murders per year. That means there are 0.0000025 murders per gun, or stated another way, there is only one AR-15 murder for every four hundred thousand AR-15s in circulation.