The 2nd amendment says:
"A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
We need to remember that when the constitution was drafted, guns were not just for hunting or self-defense or target practice. They were the weapons of war, which had just freed our country from the tyranny of the British government.
Lovely bit of hyperbole there. You also need to remember the "well regulated" bit. The militia was intended to be the army of the United States - able to drill like a professional military, use its weapons in formation like a professional military, etc. Americans no longer subscribe to that idea for a militia - as it would have entailed having every person maintain not just any old firearm that took their fancy, but one of a prescribed pattern, using a standard calibre and likely capable of taking a bayonet - because if the national defence force can't repair the military weapons or provide them with ammunition or use them effectively in a military context you don't have a militia - you have an armed mob.
Also when your Constitution was drafted slavery was still a thing, women were property, and only landowners could vote. Society changes and sometimes the basic law needs adjustment as well.
The reason no one in their right minds wants any kind of ban on guns that prevents guns from being readily accessed and used is to prevent our current government from becoming tyrannical. They have to take away the guns -or just keep making them harder and harder to get- before they can make many inroads against our other civil rights.
But, once it's impossible for the average person to get guns, all the average people are hostage to whatever happens next -the loss of free speech & the free press, being subject to search and seizures (ergo losing any guns they've hidden), etc.
No one in the USA wants that. Or, at least, no one in the USA should want that.
Is that why Canada is such a repressive hellhole? The UK a place where the state ruthlessly crushes all opposition? The Australians and New Zealanders suffer and are treated as less than human by their government?
Only the radical folk are talking complete bans - the rational majority are talking regulations - rational limitations agreed upon by the electorate.
Radicals exist in every form of human endeavour - from religion to politics to sports - and the vast majority of people do their very best to make sure the radicals don't spoil it for the rest of us.
I think if the gun control advocates want to make real inroads toward finding ways to keep guns out of the hands of those who should not have them, and lower the murder rate, they have to approach the issue with the reasons for the 2nd amendment's existence in mind.
OK - everyone who wants a firearm has to join a properly formed militia and perform military service. Said weapons will be of a prescribed type and calibre. Refresher training will occur regularly - those unwilling to fulfill their obligations to society will not be permitted to exercise their rights, those that do can.
Another way is to restrict the type of arms available to those that make it harder to carry out the sort of mass killings that are becoming more and more commonplace.
Remember: the Constitution is not an ideal, or a best-case-scenario. It's the law.
And like any law, it can be amended.
In the case of the Constitution, it's just a little more involved than repealing the prohibition on witchcraft, but no more burdensome than say repealing the 18th Amendment with the 21st. All it takes is political willpower.
In some ways, I'm jealous of those in the UK who see their government as a benevolent entity providing for the peoples and working with the overall health of the population in mind.
As a Canadian I don't view the Government as a benevolent entity, any more then most British people do. I do expect that a government made up of fellow citizens, who can be removed from power if they fail to look after the interests of the population, as the best way of doing what needs to be done.
However, I'm quite American, and at the end of the day I do not -will never- trust our government to put the welfare of the citizens above the person desires of those in power. Nor do I have to go far to find examples of this happening already -from enacting laws forcing people to buy various forms of insurance to seizing assets from those merely suspected of a crime, many of us see the rights to bear arms as a necessity. If our government falls too far out of line with what most of us want, a revolution (or the mere ability to bring one) is the only thing that will protect our free states.
What are those students doing by marching to demand gun control if not bringing a revolution? What did the civil rights movement do but bring a revolution? And what is the underlying commonality? Non-violence.
You don't need guns to change a democracy (or a democratic republic, or constitutional monarchy), you need political will.