5 CFR § 352.704 - Duration of reemployment rights.
(a) Termination of authority. Rights are not granted to persons who leave Federal employment for employment with a tribal organization after the date (December 31, 1985, at present) specified in section 105(e) of the Indian Self-Determination Act (88 Stat. 2209).
(b) Maximum period of entitlement. Entitlement to reemployment terminates at the end of 6 years following the date employment commences in the tribal organization unless exercised or otherwise terminated before that time as provided in this subpart.