Ok, I have a midlength rifle with a Troy flip up BUIS. I have been all over the net reading different posts on which zero to use, and most methods seem to be geared towards A2 iron sights. I can only shoot out to 100 yrds at my range, so which zero method would serve me better for shooting at 100 yrds or less with my set up?
Im using this zero with my rifle, 50 yard 200 meter.
http://grburnett.us/guns/ImprovedBattlesightZero.pdf
I have the fixed front sight and the MI BUIS, and its working great for me. shoots a bit high at 100 yards, but not much at all.
It’s great for most ranges I frequent or shooting at my friends farm. (sometimes I use the carry handle too set up the same way)
not sure what else would be a better option, but it’s what I use.
I am a fan of the 50/200 yard zero.
From 25-250 yards it gives the best “average” of the round being as close to POA/POI.
Quite a few people zero at 25/300 yards:
As you can see at the extreme POI is 8" above the line of sight.
Here is a 50/200 yard zero:
As you can see it gives the bullet impact much closer to the line of sight over the entire range of 25-300M. In this instance all you would need to do is place the dot or front site post on the target, and if you do your part you will not need to hold over or under for 99% of the shooting most people do. If you shoot competitions or use a BDC reticle or cams on your optic you would need to zero according to the instructions. If you do not your BDC may be quite a bit off.
With the 50/200 yard zero your POI will be about 1.5" above your POA at 100 yards.
Here is a crappy illustration I made up which shows the difference in impacts between the two zero’s mentioned above:
I started with the 25 meter zero today, but 50/200 zero makes alot more sense to me. Thanks for the posts!!! 
another vote for the 50yd/200m zero.
100yard zero is best for your situation described. 100 yard zero has the flattest trajectory, with the least amount of variation out to 100yards. You will only have to understand how low your point of impacts are in relation to your point of aim, as you will only impact low building up to 100yards.
In a combat effective reality on a human torso within 100 yards, a 50 yard or 100 yard zero would work nicely in the 100 yard range. However with a 50 yard zero, you will have a both high and low points of impact out to 100 yards. Not a big deal, but something to consider. If you regularly shot out to around 200-250 yards, then I might suggest the 50 yard zero.
50/200 works very well
+1 on the 50/200 zero. works well in my neck of the woods. 95% urban.
I also like the IBZ but Surf has an excellent point if you’re not using targets beyond 100 yards.
http://www.ar15.com/forums/topic.html?b=3&f=18&t=328143
Best.
6/3 -6, peep: dead on at 100yds (I think: bottom it out at the bottom in the dark)
6/3 -4, peep: IBZ or 50/200 (in the dark, bottom it out then come up two clicks)
6/3, 0, peep: 300yds
then simply 4 for 400yds, 5 for 500 yds etc etc.
For using the large ghost ring and the RIBZ, set it to 6/3 +1. I wouldn’t use a 100yd adjustment with the ghost because it’s not precise enough.
As Col. Santose says, leave it at 6/3 +1 on the ghost ring for your combat sight. Get a target at 300yds – simply flip the sight to the peep setting. The RIBZ simply moves it over two more spaces (only one on the 1MOA per click A2 sights) so you can get dead on at 100yds.
BTW the ghost ring is 2.5MOA -higher- than the peep.
eta: BTW those are some awesome graphs Belmont31
I am a fan of the 50yd zero. DELTA (CAG) uses a 100M zero. Both are excellent.
I tell people (when zeroing at 50 or 100) to first zero the weapon at 25yds to get the windage down and then adjust elevation when you move the target out.
C4