Social Security has one of the most powerful lobbies in the country defending it. Politicians who eagerly take on the NRA won't even mention cutting SS.
If you really believe that, compare/contrast most dictatorships with the United States, Switzerland, and Israel.
Gun control is something that oppressive rulers always try to implement as soon as possible.
However, all (as far as I know) totalitarian states have strong gun control laws. I can't think of a single one which had a permissive attitude toward the civilian ownership of guns.
I'm speaking of course of de jure gun control laws, not the de facto possession of guns by the population.