The Illinois House passed legislation last Friday to ban some semiautomatic weapons in the state.
The bill has moved to the Senate where it needs 30 votes by the end of Tuesday's lame-duck section.
The bill will outlaw .50 caliber guns and cartridges along with 20 specific types of pistols and rifles.
Spokesman for Senate President Don Harmon said, "senators are giving these proposals an extensive review and careful evaluation."
Critics of the bill said it goes against their Second-Amendment right and will not survive a court challenge.