My main interest in this topic is to convert a 2022 to DAO to avoid having to make the DA~>SA adjustment after the first shot. According to the Sig site's web page about the 2022:

the SP2022 can easily be converted from a Double-Action/Single-Action to a Double-Action Only configuration through a unique integral fire control unit.

I've gone through the manuals that came with my 2022 and didn't see how to do this.

Anyone have any instructions on how to do this?

Thanks,

wganz
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You would need to purchase a new "hammer box assembly, DAO" from SIG Customer Service.  Make sure they send you the ASSEMBLY, not the bare hammer box.  Brownells has them for $154.00 (for the SIGPro 2340).  

I'm in the process of doing this for my SIG 2340.  The 2340 is the model prior to the 2022.  But ... my parts have sat on the shelf for lack of undisturbed time to do gunsmithing.  I can't have a 4 yr old boy underfoot to do this.  I'll spare the diatribe on my child care and work situations.

See:

http://www.brownells.com/aspx/NS/schematics/schemmfg.aspx?schemid=828&m=25&mn=SIGARMS%c2%ae&model=SP2340+#NA

IIRC, the process is pretty simple for the 2340.  UNLOAD and MAKE SAFE.  Field Strip.  Remove the one-piece grip panel.  NOTE THE POSITION OF THE TRIGGER BAR.  Disengage the trigger bar pusher by pushing it down off the existing hammer box.  Be careful not to lose the trigger bar spring captured inside the trigger bar pusher.  

Drift out the lower hammer box pin from right to left (as seen as if looking through the sights from the rear of the pistol).  Drift out the upper hammer box pin from right to left.  The existing hammer box assy (fire control unit) should be removed by sliding up toward the top of the pistol frame.

Reverse the instructions to install the new DAO hammer box assy (fire control unit).  VERIFY proper TRIGGER BAR position before installing trigger bar pusher and spring.

Disclaimers:  I've done this once on an old 2340.  As I mentioned, I'll get it done again sometime on my current 2340.  I have no hands-on with the 2022.  You'd have to compare schematics.  I'm no expert ... therefore what happens to your pistol during this process is your responsibility.  Call SIG C.S. if something goes wrong or if you'd prefer they do the work for you.

HTH,

Mitchb in SC