proper way to sight in m4 ar15

[trigga]

let me start off by saying it's a pretty standard 16" bushmaster m4 type rifle. it's the patrolman model to be exact. i've always wonder what the numbering on my removable a2 handle style sights ment and watched a video on youtube. before i would do all the elevation from the back sights which had no meaning. now it's starting to make sense and i think i'm going to go back and re-sight it in properly.

from my understanding, the back elevation should be set all the way down to the 6/3. 6/3 meaning 600 meter / 300 meter, scroll a few clicks to z for zero at 25 meters which will hit at 300 meters. (adjust elevation through front sight only) once zeroed flip back to the lowest setting 6/3 and under the peep sight 0-2 meaning within 0-200 meters and flip to smaller peep for 300 meters. correct so far?

question 1: it takes 25 clicks for one revolution, from 300m to 600m, what is the value of one click?, are they timed to be pretty exact? i notice 6 clicks from 300 meter to 400 meter, then 8 clicks from 400 to 500, and 11 more to get to 600. is there an equation?
question 2: i usually shoot within 100 yards and with the smaller peep sight, now switching to the bigger peep and ranging all the way to 200, will that effect accuracy and shot placement like aim lower or higher for different distances?
question 3: is this method of sighting and dialing in the range even effective? it seems a charm but nothing is what it seems. i guess if it was designed this way it must be useful to some degree...

 

[C-grunt]

Be sure to zero with your small aperature.
1. cant help you there
2. the different distances on the dial are for the small aperature. the 0-2 is more for close range and night shooting over being zeroed for 200 yards.
3. The sights are calibrated for those distances if properly zeroed. How useful that is to you is entirely up to you.

Sighting in a 25 yards will have point of impact like a foot high at 100 by the way.

I personally like the 50 yard zero myself. Then its only like 2 inches high at 100 yards, pretty much dead on at 200 yards, and a few inches low at 300 yards.

 

[docnyt]

Some helpful hints:

http://ar15zeroing.com/

http://www.ar15.com/forums/topic.html?b=3&f=18&t=328143

 

[trigga]

I personally like the 50 yard zero myself. Then its only like 2 inches high at 100 yards, pretty much dead on at 200 yards, and a few inches low at 300 yards.

good to know, i would like to keep it as close to 100 yards as possible.

 

[postalnut25]

So the Marine Corps zeros at 36yds. That way the zero is on at 200yds. 36yds & 200yds are on the same plane as the bullet travels downrange. The only time I didn't zero at 36yds was when I actually zeroed from the 200yd line. Using the small apeture on the rear sight, with the sight set to 8/3 you want to shoot a group. Use that group to determine if you need an elevation change. If you do, adjust the front sight elevation until you get your group in the right area. Once you do that, leave the front sight alone and only adjust the rear sight elevation as you move in or farther away from the target.

 

[Quentin]

If you want a 100 yard zero and don't care about other distances, zero at 100. I'd recommend looking hard at the links docnyt gave you. If you use Molon's RIBZ you can have a 25/300 BZ, the 50/200 IBZ and Molon's 100 yard zero by reindexing your elevation knob. It's easy to do once you understand what he's talking about.

BTW, don't zero using the little Z, that's for a 20" barrel. For the 25/300 zero you'd leave the knob at 6/3 on an M4.

 

[trigga]

yeah i just read across that