Illinois gun laws are relatively strict compared to surrounding states, with background checks and a waiting period for gun purchasers. California is considered to have the toughest gun laws of any state.
Here's a look at the state laws on the books:
Q. Can you legally own a machine gun in Illinois?
A. In a word, no. Illinois law prohibits the knowing sale, manufacture, purchase, possession or carrying of "any weapon, which shoots, is designed to shoot, or can be readily restored to shoot, automatically more than one shot without manually reloading by a single function of the trigger, including the frame or receiver of any such weapon." The law also prohibits "parts from which a machine gun can be assembled."
Q. What about accessories like 'bump stocks," which the Las Vegas shooter used to fire hundreds of bullets in seconds?
A. Bump stocks, modifiers that attach to AR-15 or AK-style rifles in order to help a shooter fire at a much faster rate, are legal in Illinois and can be found at many retailers. In fact, manufacturers of the devices claim they're legal in every state.
U.S. Sen. Dick Durbin spoke on the floor of the Senate Monday in favor of stricter laws, which Democrats are pushing.
"We're not just casual observers of this violence," he said. "We are supposed to pass laws to make America safer."
Republican Gov. Bruce Rauner was asked at an event in Aurora Wednesday if he'd consider outlawing bump stocks. He did not directly answer the question, saying "I do support ongoing conversations with how we can keep people across America safer."
Q. What are Illinois' laws on assault weapons?
A. Illinois does not have a statewide assault weapons ban in place.
After Illinois became the last state in the nation in 2013 to allow gun owners to obtain permits to carry concealed weapons, municipalities were given a short window to enact their own assault weapons bans.
Cook County, Chicago, Highland Park and Evanston all passed bans, where violators are punished by fines and must alter or surrender their weapons.
Q. What do you need to buy a gun in Illinois? What about at a gun show?
A. A buyer is required to show his Firearms Owner's Identification Card when purchasing any firearms or ammunition. Getting an FOID card involves a background check.
Any seller is required to withhold delivery of any handgun for 72 hours, and of any rifle or shotgun for 24 hours, after the buyer and seller reach a purchase agreement.
That waiting period, however, doesn't apply to buyers who are dealers, or to law enforcement officers.
The seller of a gun by law needs to keep for the next decade a record of the purchase, the serial number of the gun, the buyer's identity and the buyer's FOID card number.
By requiring such records, Illinois closed what is called a "gun show loophole."
Colleen Daley, executive director of the Illinois Council Against Handgun Violence, points out that it's still easy for Illinois residents to travel to neighboring states to gun shows where background checks aren't conducted and transport their guns back across state lines.
The group is pushing to pass legislation that would require background checks on all gun dealer employees, video surveillance on the outside of gun shops and training for employees to help them identify straw purchasers.