Why is this movie in 1.85:1 and not 2.35:1 which is its OAR?
I am watching a semi pan and scan version of it!!!

2.00:1.

Long story short as possible, with what I know... Feel free to chime in here if I make a mistake. Apocalypse Now was shown in 70mm when it was first released. 70mm has a ratio of roughly 2.20:1. The film has also been shown at 2.35:1 - it's 35mm ratio. For the home video transfers, Apocalypse Now has always been framed at 2.00:1. It is the cinematographer approved transfer ratio for this film. If the box says 2.35:1 (I don't recall), it's labeled wrong.

I'm pretty sure that Redux is framed the same as the original cut has always been framed. But, I haven't watched either in quite some time. You are watching what was intended to be seen by the cinematographer responsible for the film - to the best of my knowledge. Why he chose to crop the film to 2.00:1, I have no idea. Run a web search on Apocalypse Now Aspect Ratio.

That is the way I understand it too. Vitorio Stararo (the DP) prefers a 2:1 aspect ratio for this film

Ok.

Thanks! It's just the cover says 1.85:1....

Is it just ANR? The original AN plays at 1.85:1.

2.00:1

Overscan on a 16X9 set makes it appear closer to 1.85:1... Although, on my set (calibrated to ~ 5% overscan all around), there are still very, very small black bars...

I don't know much about overscan, but what can one do to prevent it? Can one prevent it?

No. But you can minimize it. All sets have it. The trick is to get it down into the 5% & < range... You need software with an overscan grid pattern (I use Avia) and access to the menus of a set to correct it. Most sets can be adjusted in the service menus, if you know how to get there... If you are not comfortable with this, then I would suggest contacting someone in your area (at a HDTV dealer or through your set manufacturer) who knows what they are doing.