Help me understand "zero sights" on an AR

[Silver02ex]

I recently I purchase my first AR (Colt 6920). I'm tying to understand how to zero my sights, what really confuse me is the front post adjustment. I found 2 links that says the opposite things . The first say:

"Before firing the second group, I brought the front sight down two clicks, thus raising the point of aim. Here are the results"

usmc25mar-15zero - Jimmy Hots

This guy first group was shooting low so he brought down the front post.

The 2nd link states:


To raise the next shot group, rotate the front sight post in the direction marked UP (clockwise)
To lower the next shot group, rotate the front sight post in the direction marked DOWN (counter-clockwise)
To move the next shot group left, turn windage knob counterclockwise
To move the next shot group right, turn the windage knob clockwise

<broken link removed>


Now I'm confuse, I would think if I'm shooting low I would lower the front post? Every manual I've read say to bring the post to the direction you want the next group, which to me doesn't make sense.

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[t.huynh]

When you lower the front post you have to raise the barrel to center the front post in the rear peep, thus making your impact hit higher.

 

[gunnoob75]

-Move the [rear sight/scope/red dot] in the direction you want the bullets to move on paper.

-Move the front sight post in the opposite direction you want the bullets to move on paper.

The front sight is used for your standard zero only. Set your rear sight to the elevation you want it to be in. (This will change based on your rear sight. Google will help) Adjust your front sight until you are making hits on target at your chosen zero range. You will use the rear sight to change elevation/windage due to exterior ballistics from then on. Your rear sight may not have elevation adjustment in it, however, if it's a back-up style sight.

 

[PDXGS]

To move your shots onto a target use the FORS acronym
Front Opposite-Rear Same

 

[biggie24420]

I am having issues too with sighting my AR. I found the M4 military target (google for a PDF file) that tells you which site to move and raise depending on where you hit on the target.... it's the one you set at 25 yards that helps you zero the rifle out to 300 yeards. I have a bore laser too but I have never sited rifle sites so I just have to keep at it till I get it. I have seen vids on YouTube but whatever.... I just wanna take a day and shoot the darn thing till I get it right. Now having said all that, my upper is a mock dissipator so I don't know how much more difficult that will make things.... I think I am gonna start with the bore laser, move to using some .22lr rounds so I don't waste too much .223/5.56 and once I think I am close I can use some .223/5.56.

 

[parallax]

Heres a trick from a crusty old ar-15 owner. crack open a window curtain. find a light post approx. 50-100 yards away from your window, split your upper from your lower, remove bolt carrier. find a table or chair and block up your upper with books,sandbags, a dead cat or whatever.so its stable an not moving,,preferably a few yards inside the house away from the window so no one can see what you are doing... so you can look through the barrel from the bolt side.(shooting position). to catch a view of the top of the light post that you previously located out your window(make sure no one else can see what you are doing from outside your home/shed /garage or where ever you might be performing this at, or you may get a knock on the door from your local l.e.o.) looking through the barrel ,center up the light at the top of the light post,using your sandbags/books/deadcat to keep it stable((think of your view down the barrel as YOU are the bullet, where ever you are looking down the barrel is where the bullet is going to go.)),,, adjust your front and back sights to match up and center up with the view down your barrel.you can even tape up your 25meter target to a fence post outside if you have the room ...you should be within an inch or 2" of zero. No lasers needed, no bullets wasted till you get out to make your final adjustments.

 

[G1GRANDEUR]

Stop reading and go start shooting. At this point more you read more confused you get.

But yes, Lowering post will bring up the point of impact.

And most importantly, your cheek has be to on same spot every time.

 

[Key-Hay]

I like the dead cat method. Have used it for years and I'm always on paper with my 1st bullet. Just making tiny tweaks after that till I'm dead on.

I just did 2 10/22s this way. Had to use a small dental mirror to site down the barrel.

 

[Garg]

Stop reading and go start shooting. At this point more you read more confused you get.

That's great advice. The M4 guide is great as a guide. Without the full size target not so much.
I like to bench/bipod an AR at 25 yards, and using the M4 guide trick you should be able to zero in iron sights in less than one mag on pretty much any full size target. Usually takes me 9 rounds. I do three round groups.
I like to A) do the irons, B) do the red dots or scopes, in that order. Then go back and verify zero. Usually in a couple mags everything is good, till you change optics or irons that is. That's the hardest thing for me to do is resist changing things at home after I have zeroed them LOL...