The reason the conservatives do not support a gun registry, which would otherwise be an entirely sane idea, is that it’s the first step in “round up all the guns.”
There is no “round up all the guns” without first knowing their locations. Going house to house doing a deep search is prohibitively expensive.
They’ll just hide them. There are so many guns in this country, the round-up won’t even get half of them.
Any event dramatic enough to make the current crop of conservatives agree to round up all the guns isn’t going to be small, either, and most of them would involve said conservatives not wanting to give up their guns.
Mass shootings? Mass shootings by Muslims? Not enough. The response has been to want guns even more in order to shoot back.
You’d need something bordering on an ethnic armed insurrection, at which point many of them would want guns to fight against the ethnic armed insurrection.