This legislation significantly amends title 18, United States Code, to strengthen sentencing provisions for certain firearm offenses, specifically targeting repeat offenders. It focuses on individuals who knowingly violate section 922(g) by possessing a firearm after having been convicted of a felony, particularly those with a history of three or more previous serious felony convictions. The bill establishes a mandatory minimum sentence of 15 years and a maximum of 30 years for these offenders, explicitly prohibiting courts from suspending the sentence or granting probation. Furthermore, it redefines what constitutes a "serious felony conviction" for the purpose of this act. This definition now includes any felony offense punishable by a statutory maximum term of not less than 10 years, regardless of sentencing guidelines, or any group of convictions resulting in a total imposed term of imprisonment of at least 10 years. These amendments are designed to apply to offenses committed after the bill's enactment date by individuals meeting the specified criteria. The legislation also includes a rule of construction clarifying that it does not create any new right to challenge a sentence imposed under the revised provisions, aiming to ensure the new sentencing structure is upheld.