The NRA says the 2nd Amendment guarantees the right to have guns. This assertion is a misrepresentation since the Supreme Court has repeatedly said gun ownership can be regulated. In the case of United States v. Miller (1939) it said there is no right to have a sawed-off shotgun and in Lewis v. United States (1980) it said felons can be prohibited from having a gun. In 1993 the 10th Circuit Court of Appeals said, in U.S. v. Warner, that machine guns are not protected by the Constitution. The Supreme Court let that decision stand by declining to hear the appeal.
District of Columbia v. Heller (2008) is the landmark case involving gun rights. The court ruled that the Constitution’s use of the term “well-regulated militia” does not limit gun ownership to the military, the right to have a handgun for any lawful purpose is protected, and a gun owner cannot be required to use a trigger locking devise or to dismantle a gun before storing it. It also reaffirmed that gun ownership can be regulated. This was bolstered in McDonald v. City of Chicago (2008) when the court said 2nd Amendment protections apply to federal, state and local governments.
In Caetano v. Massachusetts (2016) the court said the 2nd Amendment creates a prima facie case that all bearable arms are protected. That however doesn’t mean all bearable arms are protected. It means if you want to regulate a gun you have to prove the necessity of the regulation.