Rear A2 rear site question.

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[ARCHIVED THREAD] - Rear A2 rear site question.

Posted: 2/14/2020 8:39:01 PM EDT

This is probably a newbie question. I have always used flat top uppers. I picked up a used A2 upper and the rear sight seems to have a couple degrees play in it. If you are looking at it from the top. Is that normal?? The second question is there supposed to be anything in the hole at the front of the rear sight base?? The small hole. shown in the 4th picture down in this thread.

https://www.ar15.com/forums/industry/Alignment_of_Sights/138-147708/?

Thanks

Posted: 2/14/2020 9:34:42 PM EDT

[#1]

There is spring tension built into the rear sight to hold it in a consistent position. The "play" is an intentional design element. There used to be an Armalite tech note on the subject until Armalite pulled all their technical notes off the web.

As to your other question see the assembly video below

How to install a A2 Rear Sight

https://www.youtube.com/watch?v=v_Qc3kNfPVA

Posted: 2/14/2020 9:43:34 PM EDT

[#2]

Play is normal.

The front hole is there for spring and ball detent install.

YT LINK FOR REFERENCE

Eta: holy deja vu on link.

Posted: 2/15/2020 9:56:35 AM EDT

[#3]

Thanks all. That helps... I will also double check the detent is there in the front. It seemed odd to have that much play.

Posted: 2/15/2020 11:55:39 AM EDT

[#4]

Ok I'll bite and ask you to be more specific on the "play" you are describing. The spring and detention that go in that hole are for the elevation knob. If you are feeling the typical clicks when adjusting the elevation than the spring and detention are in there. If you are referring to the play in the rear sight (the entire assembly) where you can grasp it and twist it from side to side that is normal and the spring tension build into it holds it consistently to one side.

Posted: 2/15/2020 1:14:34 PM EDT

[#5]

There can be some play where the assembly rotates around the axis of the elevation screw. Used to bother me until I noticed that the aperture is right over that axis, and so it doesn’t really move side-to-side. Still, serious highpower shooters used to get the rear sight “pinned” to prevent the wiggle. IIRC John Holligger at White Oak was the go-to guy for this mod.

Posted: 2/15/2020 7:33:18 PM EDT

[#6]

Quote History

Quoted:
If you are referring to the play in the rear sight (the entire assembly) where you can grasp it and twist it from side to side that is normal and the spring tension build into it holds it consistently to one side.

View Quote

Yep that is it... Kind of different to see a sight move around like that.

Posted: 2/15/2020 7:35:00 PM EDT

[#7]

Quote History

Quoted:
There can be some play where the assembly rotates around the axis of the elevation screw. Used to bother me until I noticed that the aperture is right over that axis, and so it doesn’t really move side-to-side.

View Quote

That makes sense... The aperture pivots right on center with the axis of the adjustment screw.

Posted: 2/16/2020 8:30:09 PM EDT

[#8]

Quote History

Quoted:

Yep that is it... Kind of different to see a sight move around like that.

View Quote

Like a bobble-head. Pretty much gets everyone the first time out.

[ARCHIVED THREAD] - Rear A2 rear site question.

AR-15 » Optics, Mounts, and Sights

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