HB 2606 proposes restrictions on the possession and transfer of certain firearms classified as "assault weapons." It defines assault weapons based on specific design features and prohibits individuals under 21 from possessing them. The bill also criminalizes selling or transferring these weapons to individuals under 21 and enhances penalties for unlawful transfers. Exemptions are provided for law enforcement and military personnel, and existing lawful owners are grandfathered in. Violations are classified as state jail felonies.