Some communities have considered -- or are even passing -- ordinances to make gun ownership mandatory. Like the Supreme Court, I believe the Second Amendment is a fundamental right, and when the Framers said that it cannot be "infringed," they meant it.
But that's a far cry from a government requiring citizens to make a purchase. Indeed, one of the chief conservative objections to ObamaCare has been the individual mandate -- a requirement that citizens purchase health insurance. Just because the Constitution secures a right to gun ownership (but not to health insurance), that doesn't mean that the (local) government has any more business requiring its citizens to purchase guns than the federal government does requiring them to purchase health insurance (although, obviously, when a local government does the regulating, the 10th Amendment problems attending ObamaCare don't exist).
It's a good idea to have health insurance. It's a good idea to own a gun. But that doesn't mean that government should intrude on individual decisions without a compelling, demonstrated need. Freedom means we're free -- to make our own decisions without government coercion. And that means that conservatives shouldn't be using government to intrude on individuals to impose policies they favor any more than liberals should.