Guess I missed the parking lot part.
The state has enacted specific requirements for carrying a rifle or shotgun on the person on a public way.
* Loaded guns: Except as exempted or provided by law, no person shall carry on his person a loaded rifle or shotgun on a public way (see exemptions below).
* Unloaded guns: Except as exempted or provided by law, no person shall carry on his person on any public way an unloaded rifle or shotgun unless such rifle or shotgun is enclosed in a case. This subsection “does not apply to drills, parades, military reenactments or other commemorative ceremonies, color guards or memorial service firing squads, so called, as permitted by law.”
* Exceptions: The provisions of these sections do not apply to (i) any officer, agent or employee of the Commonwealth or any other state, or the United States (ii) any member of the military or other service of any state or the United States, including national guard, reserves and junior reserve officer training corps (iii) any law enforcement officer, agent or employee of any municipality of the commonwealth, if the persons described are authorized by a competent authority to so carry a loaded or unloaded rifle or shotgun on a public way and such person is acting within the scope of his duties or training, or (iv) a person who is lawfully engaged in hunting and is the holder of a valid hunting or sporting license. (Chapter 269, section 12D).