Who is able to obtain court martial records and how far back can they go ?

Here is what I was able to find:

Routine uses of records maintained in the system, including categories of users and the purposes of such uses:

In addition to those disclosures generally permitted under 5 U.S.C. 552a(b) of the Privacy Act, these records or information contained therein may specifically be disclosed outside the DoD as a routine use pursuant to 5 U.S.C. 552a(b)(3) as follows:

Courts-martial records reflect criminal proceedings ordinarily open to the public; therefore, they are normally releasable to the public pursuant to the Freedom of Information Act.

Information from these records may be disclosed to the Department of Justice, the Department of Veterans Affairs, and federal, state, and local law enforcement agencies for determination of rights and entitlements of the individuals concerned and for use in the enforcement of criminal or civil law.

Information from this system of records may also be disclosed to law students participating in a volunteer legal support program approved by the Judge Advocate General of the Army.

To victims and witnesses of a crime for purposes of providing information, consistent with the requirements of the Victim and Witness Assistance Program, regarding the investigation and disposition of an offense.

The DoD 'Blanket Routine Uses' set forth at the beginning of the Army's compilation of systems of records notices also apply to this system.

It would appear that these records are considered public record, and could be obtained by virtually anyone with a good reason for doing so.