Rear Sight Problems

[azcoyote]

I put this post on the wrong section (newbie mistake) My problem is that the whole rear site moves back and forth it feels to be spring loaded when i let go of the sights it stays cocked to the left. Is this a wore out part or did something come loose? OOPS! XM15-E2S

[Rew]

an A2 type sight? If so is it screwed all the way down?

[azcoyote]

yes, im not sure what you mean?

[Rew]

The sight is adjustable for elevation. It needs to be brought to the bottom of adjustment then up a couple clicks to the range marking 3 slash 6. Zero using the front sight to adjust elevation. After that the range markings on the rear work for M855 ball ammo. I have seen people with the rear sight half way up on the adjustment screw and the front sight screwed in as far as it will go. When you do this it is easy to knock the rear sight out of kilter. ;)

[azcoyote]

I think this is part of my problem, when i put the sights all the way down it is 9 clicks past 8/3. I have read manuals and it should only be 2 clicks past 8/3 i'm not sure how to readjust this i know it has to do with the 1/6" allen screw on the top of the sights

[shamayim]

You seem to be addressing two different issues here. In your original post you were mentioning the tilt that all adjustable sights come with, due to the spring load on th left side of the sight base. The amount of the tilt will be dependant on the amount of space between the front of the sight assy and the rear of the base. The Colt uppers I have had all showed .002-.003 clearance when I inserted feeler gauges on the right side between the two pieces. The after market uppers and sight units I've had show(ed) anywhere from .006 to .013 (garbage DPMS unit). The Bushmaster piece at my house was .006.

I habitually check the clearance on any unit I get and if it runs over .004, I glue a strip of feeler gauge thick enough to reduce the clearance to .002/.003 onto the rear of the base. This keeps the tilt from presenting you with an oblong shaped aperture when you look thru the sight.

Re the zero procedure, put the 3/8 mark under the witness line. That will put the adjustment screw under the little hole in the front of the base. Unscrew the thing far enough out to lift it out of the adjusting wheel. I think 2 to 3 turns should do it. You don't have to screw it all the way out. Hold the top of the adjustment wheel while you turn the bottom of it so the aperture goes to the bottom of the base. Then click it back the other way 2 clicks, and tighten the screw.