According to the "Global Terrorism Index" that would seem to be the case. fwiw I think spree-shooters are the only situation where lack of guns do prevent gun violence, and that more would have died if these guys in the UK were carrying. That being said, spree-shootings make up the tiniest fraction of gun homicides, roughly 0.1% here even though from the news you'd think it would be orders of magnitude greater. Best ways to avoid gun violence are to not be a woman in an abusive relationship, and to not live in a black neighborhood. Do that and you've cut down most of the risk.