Requires private person to complete transfer of firearm by appearing with transferee before gun dealer to request criminal background check or shipping or delivering firearm to gun dealer in certain circumstances. Specifies exceptions for family members, law enforcement, inherited firearms and certain temporary transfers. Punishes violation by maximum of one year's imprisonment, $6,250 fine, or both, or maximum of 10 years' imprisonment, $250,000 fine, or both, for second or subsequent offense. Requires] Authorizes Department of State Police to notify local] appropriate law enforcement agency when, during criminal background check performed prior to transfer of firearm, department determines that recipient is prohibited from possessing firearm. Authorizes court to prohibit person ordered to participate in assisted outpatient treatment from purchasing or possessing firearm during period of treatment if certain criteria are met. Declares emergency, effective on passage.