Firearm violence = a firearm was involved. It doesn’t even have to be fired.

In 2007-11, about 23% of all nonfatal firearm victims were physically injured during the victimization (table 9). About 7% suffered serious injuries (e.g., a gunshot wound, broken bone, or internal injuries), while 16% suffered minor injuries (e.g., bruises or cuts). Of the nonfatal firearm victims who were injured, 72% received some type of care, with about 82% receiving care in a hospital or medical office. The victim reported that the offender had fired the weapon in 7% of all nonfatal firearm victimizations. The victim suffered a gunshot wound in 28% of these victimizations (not shown in table).

Literally firearms just being around in an altercation = firearm violence.