I was reduced from E-6 to an E-5 for inefficiency(failing pt and height weight. without the military following AR. Can this be d

You should have been provided some notice and opportunity to respond/rebut. Go talk to a JAG defense lawyer.

If I am following your circumstances, based on your years in service, you hit a retention control point (RCP) and were discharged for failing to make back rank after the reduction for inefficiency. Without knowing what aspects of the regulation you are indicating were not followed, it is very difficult to evaluate your ability to obtain redress. If you believe that your discharge was obtained in error (based on the inefficiency reduction), then your avenue is to make an application to the appropriate board in D.C. Your applications are limited in number so I strongly advise you to obtain experienced counsel in making your application.

The law presumes that your discharge is correct. Therefore, it is up to you to prove otherwise. The only way to do that is to retain experienced counsel to petition to overturn your discharge.

It's difficult to answer this question without more details. However, you should consult with a local attorney to discuss what options may be available.