Sen. Mike Stack (D., Phila.), in whose district all four Philadelphia police officers killed in the last 2 1/2 years either lived or worked, said the measure would send a message that firing a weapon at a police officer means significant prison time.
"Too many of our police officers are facing gun battles against criminals who have a complete disregard for human life," Stack said, "and it's unacceptable that our cops have become target practice for gun-toting thugs."
The bill drew wide support among law enforcement and prosecutors.
Kathy McDonald, chief of the legislative unit in the Philadelphia District Attorney's Office - and no relation to the murdered officer - hailed the provision that lifts the statute of limitations on prosecuting straw-purchase offenses from two years after the purchase to 10 years after a crime.
McDonald said federal statistics have shown that most crimes committed with straw-purchase weapons occur about 10 years after purchase.
"Is the bill the answer to gun violence? No," she said, "but it's a good start."
Handgun-control advocates said they were disappointed that the bill did not include language requiring the reporting of lost and stolen handguns - a provision the National Rifle Association opposed.
"We pushed hard to see lost-and-stolen handgun reporting included in the bill," said Joe Grace, executive director of Ceasefire PA in Philadelphia. "Unfortunately, the Senate Republicans decided to play politics with fundamental reforms that offered a level of protection for the public and police."
Grace, who said seven states have lost-and-stolen firearm reporting laws, noted that Officer McDonald was killed with a semiautomatic handgun illegally bought in South Carolina.
Eric Arneson, spokesman for Senate Majority Leader Dominic Pileggi (R., Delaware), said the bill was unanimously approved in the Judiciary Committee and on the floor, "so I have no idea what the 'playing politics' notion would relate to."
The bill:
Imposes a 20-year mandatory minimum sentence on anyone found guilty of assaulting a police officer with a firearm.
Increases penalties for possessing a firearm with an altered serial number.
Increases penalties for lying on federal paperwork to buy a gun.
Increases penalties for false reports of a stolen gun, including a new provision imposing a ban on possession of firearms for those who make false reports of a stolen gun.
Contact staff writer Amy Worden at 717-783-2584 or aworden@phillynews.com.