New Jersey Governor Chris Christie has vetoed a gun control bill that would have banned ammunition magazines holding more than 10 rounds.
The Republican governor on Wednesday returned a bill to lawmakers that would have reduced the legal ammunition capacity from 15 to 10 rounds.
Christie said in his veto message that limiting the number of bullets that guns can hold will not put an end to mass shootings.
He is calling for reforms to mental illness treatment instead.
Supporters of the bill said the limit could make mass shootings less deadly by requiring shooters to stop to reload more often, giving police and potential victims more time to react.
Christie's stance on guns is being watched closely ahead of a potential 2016 presidential run.