Credit for Military Service for Retirement Purposes
Snippet of Article: "...Credit for Military Service As a general rule, military service in the Armed Forces of the United States is creditable for retirement purposes if it was active service terminated under honorable conditions, and performed prior to your separation from civilian service for retirement. ...A deposit is the payment for a period of employment when retirement deductions were not withheld from your salary. The deposit amount is, generally, 1.3% of salary plus interest. You are not required to make this type of payment. However, not making the payment will eliminate this service from being used for title or computation purposes."
Source: www.opm.gov