The Army Court of Criminal Appeals rules are here. As previously indicated there is no “deadline” for the filing of a writ petition in this situation, but once a petition is filed several deadlines and requirements kick in. Like DMLHS I have a request in for a copy of the petition. Note that in Cheney v. United States District Court, 542 U.S. 367 (2004), the equitable doctrine of laches arose and was discussed in regard to a late filing of a petition for mandamus.
Based on the maxim that equity aids the vigilant and not those who procrastinate regarding their rights[.]
The following Rules are relevant to a writ.