10 U.S.C. § 12319

(a) Under regulations prescribed by the Secretary of Defense, a member of the Ready Reserve may be ordered without his consent to muster duty one time each year. A member ordered to muster duty under this section shall be required to perform a minimum of two hours of muster duty on the day of muster. (b) The period which a member may be required to devote to muster duty under this section, including round-trip travel to and from the location of that duty, may not total more than one day each calendar year. (c) Except as specified in subsection (d), muster duty (and travel directly to and from that duty) under this section shall be treated as the equivalent of inactive-duty training (and travel directly to and from that training) for the purposes of this title and the provisions of title 37 (other than section 206(a)) and title 38, including provisions relating to the determination of eligibility for and the receipt of benefits and entitlements provided under those titles for Reserves performing inactive-duty training and for their dependents and survivors. (d) Muster duty under this section shall not be credited in determining entitlement to, or in computing, retired pay under chapter 1223 of this title.