I SIGHTED MY ML2 AIMPOINT FOR 25YDS.
FOR MY M-4 ENTRY WEAPON. JUST CURIOS OF
WHAT THE LONG SHOT FOR THIS OPTIC.

[url]http://groups.msn.com/TheMarylandAR15ShootersSite/zeroingmethods.msnw[/url]

There is a wealth of information on this page regarding to zero.  I would suggest the 50 yard sight in.  it will give you a 3 inch difference out to 250 yards. it gives a very flat flight path.

I often make shot to steel popper targets out to 300 yards. the red dot is effective as long as you can see your target. it just makes it tough to judge long range bullet drop pass 300 yards.

I think 200 yard is max effective range considering you will be under pressure and since you only need to hit COM for that kind of job.

I've been getting approx 5.5 to 6" pattern with mil-spec parts and Aimpoint at 200 yards, and of course no benchrest.

At Blackwater, the guys I went down with were putting paper plate groupings on a man sized sillouette at 400 meters.  I, new to the Aimpoint, which I had borrowed from Ronin45 had 13 out of 15 hits at that range.  At 300 meters I was able to acomplish a plate sized grouping.

If you can see it, odds are you have a decent chance of hitting it if you have the marksmanship skills.

If you sight in 1.7" high at 50 yards with M855 out of a 14.5" barrel, it will range out like this:

50yds:   +1.7"
75yds:   +3.2"
100yds:  +2.4"
125yds:  +5.3"
150yds:  +5.9"
175yds:  +6.1"
200yds:  +5.9"
225yds:  +5.4"
250yds:  +4.4"
275yds:  +3.0"
300yds:  +1.1"

You have to spend some time at the range and chart it out whatever load you are using, but thats a close approximation.

For an LE entry gun, you're going to have a hard time justifying a 100+ yard shot either way except in VERY rare and extreme circumstances.  That however does not mean you shouldnt have it in your bag of tricks.  Murphy always shows up.

I've hit man-sized steel targets out to 400 yds. with the Aimpoint. It's not that difficult if you know the bullet drop and holdover at that range. The 3 MOA dot is one foot wide at that range so it doesn't totally obscure the target.

If you keep dot brightness at the minimal setting, the dot will be somewhat transparent and sharper, allowing for better long range accuracy.  I can say that 200 yds would be a minimum max. effective range, even if your marksmanship skills are not all that hot.  Pretty easy to hit 12" targets at that range from a kneeling position, and even somewhat easy to hit from a standing position, although, I tend to have to take a target stance to be able to hit the target.  I would say 300 yards is a good max. effective range for man size targets, especially from a prone position.