Synopsis As Introduced Amends the Criminal Code of 2012. Enhances the penalties for certain violations of the statutes concerning unlawful use or possession of weapons by felons, aggravated unlawful use of a weapon, and unlawful possession of a firearm by a street gang member. Amends the Unified Code of Corrections. Provides that a prisoner serving a sentence for unlawful use or possession of a weapon by felons, aggravated discharge of a firearm, being an armed habitual criminal, defacing identification marks of firearms, unlawful possession of a firearm by a street gang member, or certain unlawful sale or delivery of firearms violations shall receive no more than 4.5 days of sentence credit for each month of his or her sentence of imprisonment. Effective immediately.