Any person who has been convicted of a violent felony or violent crime cannot own a firearm. Violent crimes include assaults, battery, great bodily harm, robbery, breaking and entering, burglary, and others. Any crime where there is the possibility of harm coming to another or where there is a flagrant disregard for the safety and well-being of others. These can also include vehicular crimes and domestic violence.
People with a history of mental illness are prohibited from owning a firearm or having one transferred to them. The mental illness needs to be properly documented by a certified mental health professional. There are also restrictions on persons who have documented substance abuse disorders. These are in place to protect people from acts that may be out of their control.