While I am opposed to gun control, the first ten amendments to the Constitution place limits only on the federal government--not states or localities. Which means strictly and authentically interpreted, the Second Amendment doesn't prohibit gun laws on any but the federal level.
Conservatives do themselves no favors when they hypocritically make this very argument against the first amendment on "no establishment of religion" but then turn around and use it on the second.
But but but
The Supremacy Clause of the United States Constitution (Article VI, Clause 2) establishes that the Constitution, federal laws made pursuant to it and treaties made under its authority, constitute the supreme law of the land.[1] It provides that state courts are bound by the supreme law; in case of conflict between federal and state law, the federal law must be applied. Even state constitutions are subordinate to federal law.[2] The federal government possesses only the supreme authority accorded it by the Constitution.