It is only these most severe, "felony-level" offenses, which warrant a dishonorable discharge. EXAMPLES: . 1. Murder: Any killing which would be subject to the penalties of murder in a civil proceeding would also be a crime resulting in a dishonorable discharge in a military court, in addition to a maximum penalty of life in prison or death. 2. Sexual Crimes: Any serviceman found guilty of rape of a woman "not his wife" can be given a dishonorable discharge with a maximum penalty also of death. Dishonorable discharges can also be granted for a military version of statutory rape, which uses under 16 years as its age threshold. 3. Other Civil Crimes: Dishonorable discharges can also be issued for a variety of other crimes also found in civil penal code. Depending on degree and circumstance, these crimes can include theft, drug-related crimes, forgery, perjury and maiming, among others. 4. Military-Specific Crimes: Although dishonorable discharges are often issued in military court-martial procedures for crimes with specific civil counterparts, there are a few crimes which warrant this punishment that are specific to the military. Most notably among these are the crimes of desertion and sedition. Desertion is typically defined as an extended absence from one's military post with the intent to abandon military service indefinitely. Sedition (also referred to as mutiny) is typically defined as attempting to incite a rebellion or overthrow military or civil authority. . http://www.ehow.com/about_5396842_reasons-dishonorable-discharge.html
Wikipedia: A dishonorable discharge (DD) can only be handed down to an enlisted member by a general court-martial. Dishonorable discharges are handed down for what the military considers the most reprehensible conduct. This type of discharge may be rendered only by conviction at a general court-martial for serious offenses (e.g., desertion, sexual assault, murder, etc.) that call for dishonorable discharge as part of the sentence.
With this characterization of service, all veterans' benefits are lost, regardless of any past honorable service. This type of discharge is regarded as shameful in the military. In many states a dishonorable discharge is deemed the equivalent of a felony conviction, with attendant loss of civil rights. Additionally, US federal law prohibits ownership of firearms by those who have been discharged under dishonorable conditions per the Gun Control Act of 1968.