Moms Demand Action for Gun Sense under the age of 12 العنف المسلح. children in the US 555 kids killed by a gun every other day Source every other day 555 American children analysis by NBC News Source an NBC News analysis nbcnews.com 555 American children 555 children under 12 have been killed by firearms NBC News 555 American children under the age of 12 NBC NBC News NBC News 555 American children gun violence NBC reports