How many Americans have died from handgun violence since Newtown? by Brian Mann on January 9th, 2013 The grand tally, as Governor Andrew Cuomo prepares to talk about gun violence in his state of the state address, is 643. That’s according to this tally by Slate magazine. That includes seven children — a third as many as died in the incident at Sandy Hook Elementary. I’ll update this post after we hear from Governor Cuomo, broadcast live on NCPR at 1:30pm.