Shouldn't my POI only 1.5" to 2.5" higher than my POA?  How come anytime I zeroed at 50 yards, my POI always comes in at 4" to 4.5" high at 100 yards?  I always ended up adjusting the sights so I hit about 2" higher than the POA at 100 yards.

Ammunition used: generic .223 / 5.56 such as AE223, XM-193, Remington UMC, PMC etc.

Sights used: A-2 / Troy / YHM for irons.  For optic: Prismatic and Aimpoint (T-1 and M4).

I will have to go to sleep soon because I'll have to be at work at 5:00 AM tomorrow, so sorry for not replying quickly enough, but thanks in advance for any advice / criticism / ridicule / etc.

ETA: while zeroing at 50 yards, I use the black 2.5" shoot ' n see circle and stick a 1/2" orange circle in the middle.  I would then aim right at the bottom of the 1/2" orange circle and try my best to center the group in the middle of the 2.5" circle.  Basically, POA = POI at 50 yards.

50yd zero using 55 grain ammo through a 14.5" barrel gives me about 1.5" high at 100yds. YMMV

It has to do with the height of the sights above the centerline of the bore. Keep in mind that at 50 yards, the bullet is still rising to the straight line of the sights, one hundred yards it has risen past the straight line of the sights and is continuing to rise. It is not until the bullet begins it's downward arc that it crosses your sight line again. In the Military with the A2 we zeroed at 25 yards, which was even more exaggerated. What this allowed for, though, was to be able to hold center of mass on a man size target and be able to score a hit all the way out to 300 meters. With a 50 yard zero, that range will be somewhat less.

Assuming your using the same ammo at 50 that you are at 100 you should be less than 2" high unless you have a really high scope mount.  Now, if you zero with XM193 at 50 then shoot something like PMC at 100 you could be off more.

Strange...

You are correct.  Zeroed at 50 yards should have you no more than 2" high at 100 yards.  Is this with your irons or Aimpoint or both?

DOPE is collected data, not data you can look up and utilize with perfect accuracy.

Unless you're using the exact equipment (rifle/barrel/ammo) and environmental conditions, you will never achieve the exact same results that you find in ballistic tables. Use them as a guideline only, and prove and record YOUR results with YOUR equipment.

The difference in POI also depends on the hight over bore of the device you are aiming with.

I was stating that because people are saying how much their POI is effected.

OP: How do you use your irons? IE put the post ontop of the tart, or put the post right under where you are aiming?

Thank you all very much for the very helfpul replies.  I apologize for not posting and replying sooner.  I had a very tough times at work and basically was "knocked out" for a couple of days.  

I am going back to my rotation tonight, so I'll go shooting next week and maybe I can post a couple pictures here **need to learn how to post picutres**

It is with both.  I remember zeroing at 50 yards with the Aimpoint and then going to the 100 yards line.  At 100 yards, I was shooting 8.5" X 4" targets and the center of my shots were close to the upper edge of the target.  That means my POI was about 4.25" higher than my POA.

So I had to adjust the aimpoint four clicks down to get the POI about 2" higher from the center of my target.

I am just worried that with 4" to 4.5" high POI, I'd be missing at 200 yards.  I haven't shot at 200 yards lately.  The spot where I used to go shooting in the national forrest got taken over by dirt bike people, so the sherrif / park ranger says no more shooting in that area.  Before I discovered the 50 yards zero concept, I always zeroed at 100 yards and adjusted so that my POI would be 2" - 2.5" high at 100 yards and that worked well at 200.  I think I am going to revert back to my old zeroes until I can get this whole thing ironed out.

The next time I try this out I will take a note book with me and save my targets so I can actually remember instead of just recollecting bits and pieces.

Next week when I go back to the range, I am going to ditch the orange circles and just use the plain old 2.5" shoot and see circles and aim at the center.  Then I'll go to the 100 yard lines and see if that will make any difference.

Just want to thank you all again before going back to my work rotation tonight.

You know what.....it is 1:00 PM right now and I won't have to be at work until 5:00 PM - I am so tempted to go to the range right now and try it out.