Jimmy Davis, a 41-year-old London disc jockey, was saddened when he heard about the latest mass shooting in the United States. But like much of the world after the attack Monday at Washington's Navy Yard, he was no longer shocked.

The United States is a place where "buying guns is like buying sweets from a sweet shop — it's no problem," Davis said Tuesday on a busy shopping street in southwestern London. "So when we hear there are shootings like this in America, we are not really shocked. Know what I mean?"

That reaction — of horror but not surprise — was echoed by bystanders and in other places around the world following the deadly attack. As seen from abroad, the mass shooting, apparently by a lone gunman, appeared part of a new American normal, a byproduct of a treasured gun culture that largely mystifies those living beyond U.S. borders.