Plenty of other countries have a lot of firearms without the issues USA has. They have cultural issues and mental health issues are often involved in their incidents.
Also too many people think their right to bare arms was put there for personal self defence, but from memory it was to give them a means of overthrowing an oppressive government. They have people wandering around with loaded assault rises to prove a point without understanding it isn't helping them keep their right. If an amendment can give them that right then another one can take them away.
Maybe their poor education standards are an issue too, the most vocal of them seem to have trouble with basic comprehension.