In his veto message, the Republican governor rejected the idea that limiting the number of bullets that guns can hold will put an end to mass shootings, calling it a "simplistic" and "trivial" approach. The bill would have reduced the legal ammunition capacity from 15 to 10 rounds.
In the bill's place, Christie called for a series of reforms to mental illness treatment, including a new standard that would make it easier to commit people involuntarily.
"Mass violence will not end by changing the number of bullets loaded into a gun," said Christie, whose stance on guns is being watched closely ahead of a potential run for president in 2016.
Supporters of the bill, including parents of children killed in the 2012 Newtown, Connecticut, school shooting, have argued the limit would make mass shootings less deadly by requiring shooters to stop to reload more often, giving police and potential victims more time to react.
Christie signed several firearms bills into law last year, but he issued conditional vetoes of some of the more contentious ones, including a ban on .50-caliber rifles.
Democratic Assembly Majority Leader Louis Greenwald, a lead sponsor of the legislation, slammed the governor's decision and suggested Christie was pandering to the primary voters he may end up courting.
"The governor's action today can best be described with the words used in his own veto statement, 'difficult choices are brushed aside.uncomfortable topics are left unexplored.' I would imagine this is a very uncomfortable topic to have with conservative voters in Iowa and New Hampshire," he said.
Added Senate President Steve Sweeney, a Democrat: "This veto sounds like it was geared more for a national audience, rather than crafted for the streets of New Jersey."