I don't know. I could say gun control would be good thing if it could be influence everything in a global scale, however, most countries don't have the luxury of restricting access from all other states or find themselves generally closed off from notable states like say, the isolationism of North Korea.
This takes away the success of gun control and results in a general increase in one sided crime where civilians are taken advantage of. In addition, if one introduces gun control, criminals can still obtain guns illegally, that of which normal citizens wouldn't participate in or lest become criminals themselves. Gun control would take away guns from normal people and leave them only to law breakers.
Normal people who typically don't go on massacres whom have families and friends and are normal functioning parts of society with access to guns. More commonly, guns are use for recreation or personal security, not assault. Lest, we would not give firearms to even police officers. Though if that were the case, even law enforcement wouldn't do much in terms of ability to assist individuals.
Otherwise, public health care is another discussion. I personally have nothing against it, however, I could note certainly not all developed countries carry public health care nor could I say it is not without flaws. With public health care, there is a concern hospitals will become overstocked, inhibiting their ability to function properly. Furthermore, with more government spending, the action of charity would decrease with the introduction of taxes. With lower ability for spending, you further progress personal action to separate the needs of the poor for the needs of one's own family.