I live in Massachusetts. The gun law requires licenses to possess or carry firearms, even in your own home. You purchase a handgun or long gun from a Massachusetts dealer and he/she registers it with the state's Criminal History Systems Board - Firearm Support Services. For a private sale, in or out of state, you must register the purchase with the state using a FA-10 form, available from any police station. Failure to do so is a felony, carrying hefty fines and jail sentences. Also, you must possess the appropriate class of license for the firearms that you own (FID, LTC-A or LTC-B). Failure to do so is also a felony carrying MANDATORY jail sentences. Most martial arts knives are illegal, as well as automatic knives and ballistic knives.