[bearone2]

o ring or washers.

 

[Willard]

These are what they look like, if you can't find any washers locally...
https://www.sigsauer.com/store/grip-screw-set-p220.html

Or get a "Parts Kit" to which you'll have some spare springs you may need now, or later...
https://www.sigsauer.com/store/parts-kit-p220-45acp.html

 

[bblr]

PM me with your address and I'll send you the washers from my parts kit that I didn't use.