5 U.S.C. § 3326(b) provides that: A retired member of the armed forces may be appointed to a position in the civil service in or under the Department of Defense (including a nonappropriated fund instrumentality under the jurisdiction of the armed forces) during the period of 180 days immediately after his retirement. The President may suspend this requirement if a state of national emergency exists.
On 30 Aug 2016, the President continued for 1 year the National Emergency related to the 9/11 terrorist attacks. See 81 Fed. Reg. 60577, September 01, 2016 You can read the White House Notice at: https://www.whitehouse.gov/the-press-office/2016/08/30/notice-continuation-national-emergency-respect-certain-terrorist-attacks
The practical effect is the ability to obtain a civilian job after retirement without the 6 month cooling period. But also, keep in mind that if you violate an Ethics regulation or another regulation, then you also may jeopardize your security clearance.