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View Full Version : AR sight adjustment advice needed


darkgael
October 15, 2012, 06:04 AM
Here is my problem:
http://i492.photobucket.com/albums/rr287/PeteDoyle/C1B0C6D2-54A9-43A1-A6C1-4ACC9FE18CF2-173-0000001F06C64A18.jpg
I shot both of these yesterday. Prone. 100 yards. The one on the right was shot first. (the missing shots on both targets were 8s...pushed out by yours truly).
I corrected the shots to the right by going left one click - NM clicks - the result is the target on the left.
One click seems to be too much.....although one NM click at 100 yards should not cause that amount of change.
So.....thoughts and opinions.
Pete

chadio
October 15, 2012, 06:16 AM
I think the shooter compensated with aim and sight adjustment.

4EVERM-14
October 15, 2012, 06:22 AM
My first impression is "good shooting"!
The location of the two groups makes me think " Natural Point of Aim". If the second target was in a different place a new NPA might be needed. Slight position changes can influence impacts more then one might think. It is also possible that you fell into the classic sight correction trap. "One click on the gun + one click in your head." Not that I have any experience with such things.

darkgael
October 15, 2012, 08:34 AM
Thanks for the responses. The targets were, in fact, on opposite sides of the backer at the range, about two feet apart, so NPA is something for me to double check. I thought that I was careful about it but.....maybe.
I am pretty sure that I held a good center post for both targets and did not compensate. The amount of change that I needed was so small that I don't know that I could compensate that little. I won't write that off as a possibility, though.
Pete

madcratebuilder
October 16, 2012, 06:45 AM
You really need more than two groups. Shoot ten groups on a single target and average those.

The windage adjustment can be .25, .50 or 1.0 moa. Depends on what setup you have.

darkgael
October 16, 2012, 09:16 AM
MadCB: those are ten shot groups, just not very good ones. I am holding hard into the seven ring and managed to push the other shots high onto the edge of the eight ring on the left target. On the right hand target, I flubbed the first shot out to the 8 ring at nine oclock....I saw it go; the other shot was an eight to the right. I cut away the high shots so I could get a close picture with both centers. The high shots on the left target were between 11 and one oclock
Set up...NM hooded rear with 1/4 minute clicks. That is why I was suprised at the amount of movement of the centered shots.
At this point, I am leaning toward a fault in my NPA. A twenty shot group, ten at each setting may be useful.
Maybe I just need more practice.
Thanks.
Pete

PS - at my age (65), the hardest part of prone is getting back up.

4EVERM-14
October 16, 2012, 07:32 PM
darkgael,
Just wondering, do you keep the rifle shouldered to load or do you dismount the rifle for each shot?
Either way there is some movement that must be accounted for which is why I say " the key to accurate shooting is POSITION,POSITION,POSITION". Particularly for the Service Rifle. This also shows up during rapid fire when the first mag groups in a different spot from the second mag. My problems occur when my concentration fades and I look at the target instead of the front sight. I always need to kick myself in the butt to stay focused.

darkgael
October 17, 2012, 06:12 AM
Thanks for the additional thoughts.
I keep the gun on my shoulder when shooting single shots. Many times, however, since I am shooting the Sierra 77s, I shoot from the magazine. Maybe I should change that.
I hadn't considered the focus on the front sight idea.....though I have to think about it all the time when shooting Bullseye pistol.
It is the almost mirror like shift - of the good shots - from the right half of the target to the left half that is making me wonder because the only conscious change was one click left. Should have been about a half a ring.
Pete