In order to get a copy of the investigation, you need to file a FOIA request. Visit http://www.foia.gov/how-to.html for step by step directions. Once an OER is recorded in your permanent personnel file, it is presumed to be administratively and substantively correct. Thereafter, the burden of proof rests with you to provide evidence of a clear and convincing nature that the contents of the OER were either unwarranted, unfounded, or unjust, in whole or in part, thereby warranting removal. I can help you file an appeal to have the OER removed from your record. Feel free to give me a call to discuss further. The initial consultation is always free. Good luck.
The first thing I would do is request a copy of the Commander's Inquiry from your chain of command. This should not be a problem. You can certainly appeal the OER, but as you are ETS'ing you need to decide if it is worth the time/effort to do so. I would be happy to discuss further with you if you so desire.
This post is for information purposes only and does not constitute legal advice, nor does it establish an attorney client relationship with Mr. Cassara.
What you need to look out for is the coming Show Cause Board. Get off these sites and get with a Trial Defense Lawyer. An adverse OER is most always followed up with a push to separate the officer from service. I've been seeing more and more of these as the Army downsizes. You need to prepare for this now because there is no live board it's all in writing and no offense but your writing is terrible. You'll need help to put together a good rebuttal packet. GO SEE TDS!