The dept. has purchased 10 Colt 16" A3's.  Here is what the Colt manual allows.
Zeroing Sights
(According to the Colt manual)
1. The front post sight and rear sight windage knob are adjusted so you can hit your point of aim at 300 meters (328 yards).

2. The small aperture must be in the up position.

3. Set the rear sight so that the 300 meter mark is aligned with the mark on the left side of the receiver. Sights with removable carry handle (us) with the “Z” setting set to “Z”.

4. During zeroing, only the front sight post and rear windage knob are adjusted to move the point of bullet impact on the target.

5. If you are zeroing on a 25 meter (27 yard) range, adjust the rear sight elevation knob one click up from the 300 meter mark and leave it that way while zeroing.  Leave sights with “Z” setting to “Z”.

6. Aim at the target and fire.

Qualifying starts at the 50 yd line and ends at the 100 yd line with a total of 10 rounds fired. I haven't been able to get into the armory and check the A3 rear sights to see how they are set up as far as at what point do they bottom out compared to the elevation wheel numbering.  The dept. will not allow any changes to be made to the screw that would allow the elevation wheel to be rotated such as in the IBZ.  The "Z" means just that, zeroing and nothing else?  Is there a 6/3 setting along with the "Z"?  If zeroing is done at the 50 yd line using the "Z" setting will the remaining meter markings on the elevation wheel still be valid?  Should zeroing be done at the 25 meter/27 yd line and then done again at the 50 yd line and adjustments be made if necessary?  Or would it be just a waste of ammo?  After zeroing and moving on to qualifying should the rear elevation wheel be moved to the 6/3 position?  I take it there would be no change in the use of either the small aperture or the large aperture?

No bashing please.    

groups.msn.com/TheMarylandAR15ShootersSite/zeroingmethods.msnw has details of several different zeroing methods.  

Here's what you need to do:

- Use the small aperture for better accuracy.
- Make sure the rear sight is as low as it'll go.
- Zero at 50 yards.  The 50 yard zero (aka Improved Battlesight Zero) provides the flattest trajectory out to 220 meters.  
- Lastly, and heres the important one, please don't let yourself or any fellow officers think that being able to put 10 rounds into a target at 100 yards makes them qualified with this or any other weapon.    Everybody needs to spend some time with a good instructor especially if they or somebody else's life is going to be on the line.  Any halfway decent instructor will take the time to explain how to zero the weapon as well as put you through some exercises that will make you familiar with the amout of holdover you'll need at varying ranges.

Buzz:

The Maryland site has loads of great info.

I zero a rifle based on the target, range, and need.

If you are concerned about qualifying from 50 to 100 yards on a man-sized silhouette, I would put a decimal target at 75 yds and get a good zero.  If I was worried about speed, I'd use the large aperature.  Precision? Smaller is better.  If the final stage is putting two rounds in a four inch bull at 100 yds, I would zero for that.

I also wouldn't worry about the markings on the sight.  For the most part, they are for ranges impractical for LE.  Zero the rifle for what you need to do.

Most training centers have programs especially tailored for LEA.  Do some checking and see which one would come to your site and provide cost effective training for your anticipated needs.

JMHO......SRM

Hey Kevin, I think Hoplophile is right on ...

Here's a direct link to the Improved Battle Sight Zero: groups.msn.com/TheMarylandAR15ShootersSite/improvedbattlesightzero.msnw