1.  Imprisonment.  Under instructions issued by the Governor, a sentence of imprisonment adjudged by a court-martial, whether or not the sentence includes discharge or dismissal and whether or not the discharge or dismissal has been executed, may be carried into execution by imprisonment in any place designated as provided in section 408. Persons confined in a correctional center not under the control of one of the military forces are subject to the same discipline and treatment as persons committed by the courts of the State.  

2.  Forfeiture.  Whenever a sentence includes both a forfeiture of pay and allowances and imprisonment and the imprisonment is not suspended or deferred, the forfeiture may apply only to pay or allowances becoming due on or after the date the sentence is approved by the convening authority.  

3.  Effective date.  Sentences of courts-martial are effective on the date ordered executed, except another date may be required by subsection 1 or 2.