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AR15.COM
11/7/2016 7:33:30 PM EDT
Hi all. Need help/advice. Trying to do quick 25M zero today. Wind age is right on, nice tight groups however, hitting 4" low...rear sight is bottomed out. NM SA rifle, Hbar...even on a rest. A 12 o'clock hold on a medium size shoot n see target hits dead center. No idea WTF...my sight picture? Front sight too tall? Any help would be appreciated, Thanks
11/7/2016 7:41:28 PM EDT
[#1]
The front sights on 16" and 18" models are higher posts by design.  Maybe one was installed by mistake on your rifle?
11/7/2016 7:56:31 PM EDT
[#2]
If you're hitting low, you want to move rear sight up, not down.
11/7/2016 8:19:14 PM EDT
[#3]
Quote History
Quoted:
If you're hitting low, you want to move rear sight up, not down.
View Quote


This
11/7/2016 8:34:38 PM EDT
[#4]
Mane, but I thought that the sight went down to move the strike up, Will give that a "shot"...lol
11/7/2016 8:38:24 PM EDT
[#5]
It's a 22" match barrel. But thanks, I'll give that a try.".....
11/7/2016 10:01:26 PM EDT
[#6]
They are correct.  With a front sight adjustment, you always follow the bullet impact (shoot low, move sight DOWN).  With a rear sight, you have to move opposite, or the direction you want to move the impact (Shoot low, move rear sight UP).
11/8/2016 1:36:43 PM EDT
[#7]
Standard amount of rear clicks for a rear sight to zero  is 6-8 on an M14/M1A/ Garand.  If it's a NM rear sight it's 12-16.  I have a loaded and I'm at 16 clicks up for a 50 yard zero.  To my recollection.  It's been a while since I zero'd it.  And it has a scope on it.  But yeah,  your brain is having it backwards lad.  It sounds to me like it's doing just as it should.
11/8/2016 8:18:15 PM EDT
[#8]
The next time you go to the range take an allen wrench that fits the front sight base. You want to move the rear sight to the center of it's adjustment and slide the front sight left or right in order to obtain a mechanical windage zero. Tighten it firmly once the zero is set.

From there dial your bullet impact up by raising the rear sight. If you are 4" low at 25 yards you're going to be raising it a lot, like 10-14 clicks up from the bottom.
11/10/2016 11:08:15 AM EDT
[#9]
Quote History
Quoted:
They are correct.  With a front sight adjustment, you always follow the bullet impact (shoot low, move sight DOWN).  With a rear sight, you have to move opposite, or the direction you want to move the impact (Shoot low, move rear sight UP).
View Quote


ETA: Glad you got your answer. Happens to all of us. You might catch me using my fingers to imitate front and rear sights to figure out which way to adjust the front sight on a standard front sight base.

Something to consider... If you zero at 25yd, that'll be like 8+ inches high at 100yd. You might want to consider 200/300yd equivalent zeroes. That means zeroing at ~35yd for 300yd Z or ~50yd for 200yd Z. But the close distance Z is different between guns and calibers, so you'd need to shoot that distance to confirm.

11/12/2016 8:43:04 PM EDT
[#10]
never mind