Thanks. When you have families who have been Marines, you would get to know that yell, including at their graduations. One reason not to have a dialogue with those who don't get it. Saying "oh rah" and "ooh rah" do not sound the same. The "oh" sound is a shortened one and that goes to Arnold Horshack whenever he thinks he knows the answer and blurts out the distinctive "oh! oh! oh!"
response while raising his hand to Mr. Kotter's question thinking he has the right answer but doesn't. It'd be silly to say "oh rah! if not highly insulting for not saying it right in the Marine Corps. So, the "oh" one is quite stupid while the "ooh" rah
is the correct sound and pronunciation.