According to Massachusetts state law, it is illegal for a civilian to carry a dangerous weapon in their vehicle or into a building in most circumstances. Exceptions exist for those who are licensed to carry a firearm or those who are carrying a firearm in their vehicle while at their own residence. People may also be authorized to carry a firearm outside of their property or could obtain the express permission of the building owner or manager to carry.
Firearms are not the only weapons that can lead to dangerous weapons charges. Knives with automatic spring release devices, switchblades and any other knife that allows the blade to be drawn from a locked position are illegal to carry in a vehicle. Other illegal weapons to carry in vehicles include machine guns, daggers, blowguns, and metallic knuckles.
The penalties for carrying such weapons depend not only on the type of weapon but the location in which it is carried. The unauthorized carrying of a firearm in a vehicle holds a maximum house correction sentence of two and a half years or a maximum of five years at a state prison. The minimum sentence for jail or house of corrections is 18 months. When someone commits a dangerous weapons crime in the process of an arrest or disturbance of the peace, the minimum sentence is two and a half years in state prison or six months in jail.
A criminal defense attorney may be able to help clients with weapons possession charges negotiate a lower sentence if it is a first-time felony charge. Because vehicles are generally regarded by the law as less private than residential property, routine traffic stops may lead to a weapons possession charge. The fourth amendment as it pertains to unreasonable search and seizure may be one avenue of defense in such cases.
Source: The 188th General Court of The Commonwealth of Massachusetts, "General Laws Ch. 269 Section 10", October 29, 2014