In a moment of weakness I picked up a Nikon p223 3x9 on sale at academy. My ar is an a3 style upper. Ive been looking at the nikon m223 mount- will that clear front sight post from showing in reticle? What other options are worth looking at?

Burris PEPPR is a good one

I used this Leupold mount to attach my 3x9. You can not see the front sight at all, and it keeps the scope about as low as possible. I really like this mount, and it is easy to attach. Mounting hardware is durable and large enough to prevent stripping/rounding. I don't have any experience with the Nikon mount. The leupold mount is kinda pricey though at 100$.

http://swfa.com/Leupold-Mark-2-IMS-1-Integral-Mounting-System-P48109.aspx

The nikon is about 20$ less

http://swfa.com/Nikon-M-223-1-Mount-P61580.aspx

Here is the Burris PEPR, I have one that is labeled with the SWFA name brand. It is considerably more chunky and less refined. Plus it has a million machine screws( six per ring actually).

http://swfa.com/Burris-AR-PEPR-1-Scope-Mount-P12624.aspx

I have the SWFA SSALT. Nearly identical to PEPR, but not QD...Rumor is their made by Burris.

You will not see the front sight in your view unless you focus hard on it. It will not obstruct your shot.
All the above mounts are great to use I have 2 of the Burris PEPR and a LaRue

Burris PEPR gets a lot of good reviews.

NOBODY complains about Larue, except for the price.

I have a Larue for my Aimpoint, and my brother has one for his Vortex. Solid mounts, as you would expect.

I use ADM
I am constantly swapping optics around.
They work.

I have a Burris PEPR and am very happy with it.

I've had Burris PEPR, SWFA SSALT, and Larue mounts on a few rifles and you can't go wrong really with any of them

La Rue or BoBro are the ones I am looking at. Also ADM

That is only a rumor. There is no truth in that statement to my knowledge.

I personally use Bobro, but I have a couple ADM's and they work well.

If you plan to never take it off, go with the SWFA SSALT mount. It will serve well for a long time.

I just ordered a Leupold Mark AR Firedot 1.25-4X TMR. I'll post once I try it out.

I have the rock river arms scope mount on my rifle, its not bad but I can't say that I would recommend it. I am thinking about getting an aero precision scope mount

I use an SWFA SSALT on my DPMS 308 and NO complaints!
SWFA all day!