The White House is looking at various options, and the scope and details of the president’s approach aren’t clear. One possibility likely to be considered is a ban on high-capacity magazines, the devices attached to firearms that store large numbers of bullets and reload them rapidly.

A 1994 ban on assault weapons that expired in 2004 included a ban on ammunition magazines that held more than 10 rounds. Recent shootings, including the one Friday, have involved firearms with much more capacity, allowing a shooter to fire many more shots before having to reload, which could allow someone to intervene.

Assault weapons are a class of semiautomatic firearms, those that require a single pull of the trigger for each shot fired and then load the next round automatically. Under the 1994 law, there were 19 models of firearms and copies or duplicates of them that were banned, along with semiautomatic rifles that accepted detachable magazines and possessed at least two other characteristics, including a protruding pistol grip, flash suppressor or threaded barrel or a folding or telescoping stock.