Ever notice how some A2s have a lot more play or wobble in their rear sight where as others are very tight and won't move much at all?  This is most apparent when the rear sight is raised elevation wise to any degree vs. being bottomed out into the receiver.  Some have a lot more torque to them.  Does anyone know what the reason for this is, or how it can be tightened?

Dunno if this helps any or not.

I have an Armalite NM sight on my NRA Service Rifle.  What was posted in the letter from Armalite is true - there is absolutely NO rotation of my rear sight base, no matter how many clicks of elevation that I have on it.

That being said, the rotation inherent in a "regular" A2 sight base has absolutely no affect on windage or elevation.  On the A2 sight the rear sight leaf that you are looking through is directly over the center of the elevation screw.  It the sight rotates a little the sight leaf may be presented at a slightly different angle, but it is still in the same place as to windage.

Getting rid of the rotation is only important to those who have hooded rear sights, as used in Service Rifle competition, and perhaps have some sort of a lens fitted inside the rear sight hood.

Now, if there is play or wobble in the elevation screw itself (which I've never heard of, but I guess it could happen), then either the screw is undersized or the tapped hole in the elevation wheel is oversized.  This could be a problem.  If that were the case on one of my rifles, I'd probably try to buy a new elevation wheel (Make sure it's the same thread pitch as your elevation screw.) and see if that's the issue.  Otherwise an entire rear sight is not too expensive.

Anyway to tighten the rear sight though so it has less wobble?  I have multiple identical uppers from the same manufacturer.  Some rear sights have a lot of wobble, some are very tight and hardly budge at all.  There has to be a reason for the discrepancy?

Yeah.. IIRC Brownells sells an A2 sight installation/tightening tool.

Have a link?

Think this is what he's talking about

Ok, thanks.  Any info on how to use it to tighten down the rear sight?  The information video is in regards to A1 sights!