What I have:
16" 300blk with magpul BUS
8" 300blk - (not complete, waiting on barrel)
762SDN6 (waiting on approval)

I took my 16" 300blk to the 75yrd range for a function test. Both supers and subs cycled w/o issue. The supers were consistent from 25-50-75yrds, but the subs just drop like rocks. How do you all set up your optics for such a change in ballistics? I'm thinking I should set up the 16" for supers only and the 8" for subs? I originally wanted a 1-4x scope for the 16", but after seeing these results, I think a red dot might be better suited. The 8" will most likely have MBUS and a laser for CQ shots.

Also, how will the suppressor change ballistics? THANKS!

Heres where I went with my 8" blackout.

http://www.300blktalk.com/forum/viewtopic.php?f=128&t=79621

How about something like a PST 1-4 or Mark AR 1-4. Both have external turrets to dial elevation and mil-based reticles is you would rather hold than dial.

My DD 300 BLK barrel just came in so I'm interested in optics choices as well.

The Eotech with 300 blackout reticle looks interesting.  The first dot is for 100 yards with supers and the 2nd dot is for 300 yards with supers.  I'm thinking about going this route and adding a 3x magnifier behind it for longer shots.  Either that or a 1-4 optic

It was mentioned that a 100yrd zero with supers was a 50yrd zero with subs. Is that accurate?

As a generalization,  yes. Zero at 100 with supers and you will be very close with subs at 50.
Consider the falcon optic mentioned as a lower cost alternative to these...
http://blogs.militarytimes.com/gearscout/2012/08/29/300-aac-reticle-appears-in-4x32-browe-combat-optic/
http://www.impactguns.com/leupold-mark-4-mrt-15-5x20mm-m2-300-blackout-reticle-lit-113594-030317135942.aspx
I kind of figured that if these major manufacturers consid it close enough to use it in their high and optics,its probably close enough for the average user.

In practical use,  zeroed at 100 yards with 125 grain Federal Premium match I am generally within an inch with 208gr hornady, 220 SMK's and 245 grain Missouri bullets rnfp.
Considering the height over bore issues of shooting an AR 15 at close range I consider this pretty dang close.