Does anyone have instructions on how to change out the A1 rear sights/aperture? I tried finding it online but have had no luck. I'm changing the rear aperture with Ashley's same plane rear sights. Any help is appreciated! Thanks.

Ok I'll try.
On the adj. wheel on the right side, if you look there is a roll pin you will need the proper size punch to drive out.
Lift off the adj. wheel
Carefully capture the spring and plunger that goes in behind the wheel that holds the adjustment from moving.
Use a flat screw driver remove the screw from the aperture and reciever.
And you will see a flat leaf spring under the aperature don't lose it you need it .
Reverse operation to install.
Once you look at it a little bit, you will see how easy it is, way easier than trying to explain it.

Unless you want your upper to look like a turd, don't use a screwdriver to twist the aperture off the windage screw.  Just twist it off by hand.  Same thing on reassembly.  The only tool you need is a 1/16" punch and something to tap on it with.  Also, it is easier to reassemble if you don't knock the roll pin out completely, just knock it out enough to free the hub from the adjustment screw.  

Thanks, guys. I'll give it a shot again tonight.

Well, didja get it?

Thanks all.  I once I found that first pin (which I didn't notice at all until it was mentioned),  it was cake.