Do access to guns turn people into killers, or is killing a cultural thing?

In Norway and the U.S., guns are easily available. In most other countries they rather hard to get. There are exactly the same number of guns per capita in Norway and the U.S. Still, the number of killings per 1000 citizens is ten times as large in the U.S. as in Norway. Could the old NRA slogan be right after all; 'Guns don't kill people, people kill people'?

Access to gunsCultural