It's hard to say exactly. Each state may have it's own definition so you should seek an attorney licensed in each state to be sure. It may be that since a special court-martial normally contains charges under Titles 10 and 18 of the United States Code and that they would look to a federal definition.
Generally, the federal courts will look at it like this, if the maximum term of imprisonment authorized is:
(1) life imprisonment, or if the maximum penalty is death, as a Class A felony;
(2) twenty-five years or more, as a Class B felony;
(3) less than twenty-five years but ten or more years, as a Class C felony;
(4) less than ten years but five or more years, as a Class D felony;
(5) less than five years but more than one year, as a Class E felony;
(6) one year or less but more than six months, as a Class A misdemeanor;
(7) six months or less but more than thirty days, as a Class B misdemeanor;
(8) thirty days or less but more than five days, as a Class C misdemeanor; or
(9) five days or less, or if no imprisonment is authorized, as an infraction.
Ordinarily, a special court martial would be of the level misdemeanor. For drug offenses, the quantity of the drug will control. You need to contact a JAGC civilian attorney with your court documents and Page 9 for page a better recommendation/opinion.