If we're going to talk numbers - most gun deaths involve gang/drug activities.
The real numbers once you remove suicide and gangs all point to mental illness and DV/Violent individuals.
In the UK, where the civilian population does not carry arms and even most cops don't, the police fires a few hundred shots per year(!) with a population of 60 million. In the entire post war era (The Troubles aside) less police has been killed than in the US in a year.
So if you care about the safety of law enforcement an arms race has bad consequences for everyone. And the militarization of police is another bad consequence.
Gang membership as traced by law enforcement is not something super formal.
I found this, although it mostly contradicts your claim (with the exception of gun deaths due to assaults on people in the age range 5-34): https://web.archive.org/web/20180829034947/https://injuryfac...