(How's that for a thread title? I figured that would work better than a bolded 'ZOMG sitez no work!!!one!'  )

I was working on Zeroing my two ARs today at 50 yards, doing the IBZ that is detailed here at the site.  (They had been originally zeroed on the normal 25 meter combat zero.  Which, I found to be inadequate for hitting steel plates out to 300 yards in 3-gun shoots.)  Both guns were shooting low.  My A2, which has a fixed front sight tower, was about 2.5 inches low.  So, I cranked the front sight down about 6 clicks (sight post rotated abut 1.5 full turns), and it hit bottom.  Now, for that rifle, it's just about on, although still a bit low, POI moved up about a little over 2 inches.  

Now, on my Bushmaster Varminter, I have a YHM flip up front (the one sold by Bushmaster that clamps around the gas block.)  It was shooting lower at 50 yards, about 4-5 inches.  Again, I turn the front sight post about 1.5 full turns, and it too bottoms out, and the POI moved up about 2.5 inches.

Both rifles shooting the same ammo, some of our favorite 50 grain Federal bulk pack stuff.  50 Grains moving along at a bit over 3300fps per the chrony.  They are extremely accurate through my Varminter with it's scope.  Anyway...

My friend and I both thought that was a bit odd.  But, before I go and order new sight posts or something else drastic (like an ACOG, for example) am I doing something wrong?  At the beginning of this, both rifles' sight bases were flush with the sight tower base, and the Rear Sights were at their Zero Point (the 8/3 and 6/3 marker, and the sight all the way down in the handle.)

The 50 yard zero isn't the end all be all.  Functionally, it is no better than anything else...you just have to know where your rifle and load shoot at a given distnace.

I zero my irons and Aimpoint at 33 yards POA/POI on a standard M 16 tgt. and it has worked well.  

Know your rifle and it is fine.

Quoted: The 50 yard zero isn't the end all be all.  Functionally, it is no better than anything else...you just have to know where your rifle and load shoot at a given distnace. I zero my irons and Aimpoint at 33 yards POA/POI on a standard M 16 tgt. and it has worked well.   Know your rifle and it is fine.

Well, I found that the 9" POI range of the 25 meter zero was a bit harder to guestimate when trying to hit an 8" plate at 200 yards.  I think the 50 yards 2" range will be a bit less drastic to work with, especially when under the clock at a match.

But, my question isn't about my choice of zero, it's wondering if I'm doing something wrong with the front sights....

Did you do the modification to lower the rear sight below the 6/3 and 8/3 markers?

Quoted: Did you do the modification to lower the rear sight below the 6/3 and 8/3 markers?

Nope.  That's my problem.  I was thinking about it when I woke up this morning, and I realized that I hadn't done that part.  Brain fart on my part. I was thinking....if it is zeroed at 25 yards, why can't it go down further ..... OH!  gotta lower the rear sight block...duh.