The Supreme Court has declined a case brought by the gun lobby to try to halt New York's tough new gun laws, which limit bullets and reclassify assault weapons.
The justices declined to hear a challenge to the law, which makes it difficult for residents to get a licence to carry a concealed handgun in public.
They also reclassified "assault weapons". Now any gun with features such as pistol grips or detachable magazines should be registered as "assault weapons" where previously they were not.
It is estimated that around one million guns now fall under the new reclassification, which came into force on Monday, along with the restrictions on ammunition.
The New York affiliate of the National Rifle Association claimed that the law violates the constitutional rights of law-abiding citizens to "keep commonly possessed firearms".
The legal wrangling comes amid an intensifying congressional debate on new federal gun control measures and after both Colorado and Connecticut signed new tougher restrictions into law.
The issue has resurfaced prominently in Washington in the wake of the school shooting at the Sandy Hook Elementary School in Newtown, Connecticut, in December.
Adam Lanza shot dead 20 children and six adults, walking into the school with a semi-automatic assault weapon and firing 154 shots in five minutes.
Two senators announced last week they had reached a bipartisan deal on expanded background checks.
But gun control legislation still faces a difficult path, with Republicans careful not to take any actions that could be considered to be infringing on the constitutional right to bear arms.