The Supreme Court struck down provisions of the Firearms Control Regulations Act of 1975 as unconstitutional, determined that handguns are "arms" for the purposes of the Second Amendment, found that the Regulations Act was an unconstitutional ban, and struck down the portion of the Regulations Act that requires all firearms including rifles and shotguns be kept "unloaded and disassembled or bound by a trigger lock." "Prior to this decision the Firearms Control Regulation Act of 1975 also restricted residents from owning handguns except for those registered prior to 1975."

And, although the Supreme Court's decision adopted the broader, individual-rights interpretation of the Second Amendment, the Court also made it clear that the right to own a gun continues to have a number of significant qualifications or restrictions, including:

Not everyone can own a gun. The right does not extend to felons or the mentally ill.
Guns cannot be carried everywhere. Laws forbidding individuals from carrying firearms in "sensitive" places, such as schools and government buildings, will probably stand.
Certain restrictions on the sale of guns are allowed. Laws imposing conditions and qualifications on the commercial sale of firearms will most likely stand.
Individuals do not have the right to carry certain types of guns. The right does not protect guns that are not generally owned for lawful purposes, such as short-barreled shotguns. Just what kind of handguns may be possessed is not explicitly set forth in the opinion (apart from the one specific reference to sawed-off shotguns, which are not allowed). The Court did endorse the "the historical tradition of prohibiting the carrying of 'dangerous and unusual weapons,'" but did not state whether such weapons include assault weapons or semi-automatic weapons.
Concealed weapons. Laws forbidding people to carry concealed weapons on their person (or in a place close at hand, such as the glove compartment of a car) probably remain valid.
Sentence enhancements. A variety of criminal laws provide for increased punishment of offenders who use weapons when committing a crime. Heller does not affect the validity of these laws.

Based on previous court rulings striking down gun laws in D.C., Chicago and elsewhere, “there is no longer any basis on which this Court can conclude that the District of Columbia’s total ban on the public carrying of ready-to-use handguns outside the home is constitutional under any level of scrutiny,” Scullin wrote in his 19-page decision, which was unsealed on Saturday.
“Therefore, the Court finds that the District of Columbia’s complete ban on the carrying of handguns in public is unconstitutional.”

The case against D.C., which is the only jurisdiction to ban people from carrying handguns in public, was brought by several people who tried to obtain permits for carrying a weapon but were denied.

Scullin’s ruling in Palmer v. District of Columbia will prevent police from enforcing the law, at least for the time being.

Despite these rulings, the NRA contends that the strict gun laws in Washington, D.C., make it all but impossible for people to carry firearms around the city.

Twenty-one residents have qualified for concealed carry permits in Washington, D.C., according to the police department.
"They want to be more restrictive than they’re allowed to be under the Constitution, which is the problem,” an NRA official told The Hill. “They’re not looking to make it reasonable for law-abiding citizens and difficult for criminals. They’re making it difficult across the board.”

But the new Republican legislation could change that.

The Second Amendment Enforcement Act would expand the city’s concealed carry laws, making it easier for residents and tourists from other states to legally carry firearms in Washington, D.C.

"A lot of American tourists visit Washington, D.C. They want to view the Capitol and the museums, but they also want to be safe," the NRA official said.