Im changing between 25 and 30 A2s to night sights and this is one operation I have yet to perform. I could use detailed step by step instructions in sequence. I know I can get them apart and back together again but I dont want to experiment and I dont want to waste a lot of time on the wrong side of the learning curve. Best answer gets a good used GI 30!

Did I win?

Get this book The AR-15 Complete Assembly Guide—How to build your own AR-15—by Walt Kuleck with Clint McKee from [url]http://www.scott-duff.com[/url]

It is well written and has detailed photos of all aspects of building your own. The assenbly of the A2 site is well done.

Yeah, thats a good book.

So, if these are the only two answers I guess I win. [beer]

using a roll pin punch, drive out the roll pin from the drum.
be sure to catch the detent and spring weh you remove the drum.
unscrew the windage screw, removing old apeture, replacing it with the H3 version, and screw the windage screw inte the new apeture.
make sure the hole for the roll pin ends up aligned near vertical.
add a dab of grease to the detent (ball bearing) and it's spring... this makes things much easier to get back together.
modifying a pair of needle nose pliers with a small notch near the tip to hold the roll pin makes the job much easier... they don't need to be Snap-On, some cheapies form the 99¢ store, gunshow or flea market/swap meet will do.
final assembly requires you to press the drum into place, hold it and the roll pin in alignment and gently hammer the pin with the punch... its a 3 hand job if you want to make it easy.

Sears sells the roll pin punches.

have spare roll pins, detents and springs on hand ahead of time... just in case.

Fixer can I get yer address???? I think this contest is over! [beer]

e-mail sent, happy to help!