CHICAGO — As Chicago struggles to quell gang violence that has contributed to a jump in homicides, a top elected official wants to tax the sale of every bullet and firearm — an effort even she acknowledges could spark a legal challenge.

Cook County Board President Toni Preckwinkle will submit a budget proposal Thursday that calls for a tax of a nickel for each bullet and $25 for each firearm sold in the nation's second-largest county, which encompasses Chicago.

Preckwinkle's office estimates the tax will generate about $1 million a year, money that would be used for various county services including medical care for gunshot victims. Law enforcement officials would not have to pay the tax, but the office said it would apply to 40 federally licensed gun dealers in the county.