This bill modifies the provision of the Maine Criminal Code defining "machine gun" to include any part or combination of parts designed and intended for use in converting a weapon into a machine gun. The bill enacts a provision that makes it a Class D crime for a person to knowingly possess a rapid-fire device without authority to do so. A rapid-fire device is a device, part or combination of parts that is not a machine gun and that materially increases the rate of fire of a semi-automatic firearm above the rate of fire of the semi-automatic firearm absent the device, part or combination of parts. With respect to the definitions of "machine gun" and "rapid-fire device," the bill provides a nonexhaustive list of examples describing the types of devices that would satisfy each general definition.