The NRA and its supporters say larger-capacity magazines are popular, with millions already in the possession of American gun owners who want them to feel secure against criminals armed with similar firepower.

They also contend citizens have the right to such weaponry to protect against future government tyranny, which they say was the intent of the Second Amendment's right to bear arms.

Erickson Hatalsky rejected any inference by the NRA or its supporters that Obama's proposals or other measures being discussed in Congress amount to taking away people's guns.

She praised the president's strategy of presenting a broad package for Congress to consider, saying: "It behooves people who are working on this issue to keep the NRA arguing about lots of different issues, rather than allowing it to concentrate on one and defeat it."