Optics mount for 220?

[New Hampshire]

Alright, Ive been tearing my hair out looking and searching for a no drill/tap mount for my 220ST.  I looked to everyone from B-Square to Aimtech.  I know they have one for the 226, but does anyone know of one for the 220?  I want to put a dot scope or handgun scope on it so I can use it for Coyote hunting, but I still want to be able to return it to stock at will as this is the gun I carry concealed (even if its not that often.)  So am I looking at a lost cause?  At this point Im thinking of just giving up and getting adjustable sights.  Pachymar makes an interesting one Im looking at.  But A mount would be soooo much better.
Thanks,
Brian M.

[swifty]

Why do you check our the Doctor holographic sight? They claim it is used by the FBI. It weighs 1 1/2 ounces.
http://www.docteropticsusa.com/

I have an Ultradot for target shooting on a S&W model 41, and part of the time I can't  pick up the red dot. It has to be exactly square to my line of vision to be able to see. My guess is the FBI would never mount a red-dot optic on their guns.
You still may have to drill and tap. Take the slide to someone who has experience and a milling machine.They should have a device that will help calculate the exact center of the slide. The doctor has windage adjustments. The main shortcoming of this sight is it is a pain to change elevation. Set it at a distance you often use and learn how much to hold over for the longer shots. Set at 25 yards and learn how much to hold over for 50 yards for the bullet & powder you are using.

[swifty]

Here is a web site for a mount for optics on your Sig P-220
http://www.egw-guns.com/