This issue won't end up being solved any time soon. American people are so attached to guns that its embedded into their culture. Taking away one such aspect and feature is incredibly invasive and discouraging to gun owners. Psychologically speaking, people are very emotionally attached to inanimate objects, and are unwilling to let them go. Nowhere else in the developed world are people culturally attached to guns as they are in the US, not even Eastern Europe. Honestly I don't even get what the deal is even with killing & hunting animals for recreation. Ducks taste gross and are concentrated with heavy metals, so they're just trophies, big deal (could pass if they were not wasted, well maybe we need to control Mallard populations, but lets ban feeding bread to ducks). As for semiautomatic and automatic weapons, I don't even see them being banned or confiscated any time soon. All in all, the lifetime far alt-right Supreme Court justices will vouch for unlimited guns when they're appointed, and may never flip-flop on the issue. It would take a Constitutional Convention or support of States to change anything. For now, the short term solution isn't to spend more money and time on police officers or metal detectors. There will always be an exploitable boundary surrounding a large place (airports, schools, etc.). It's best to invest in mental health facilities, cyber security and espionage, intelligence, and education.