Found on floor where I clean my guns. Can anyone identify as part of Smith & Wesson 500 Magnum, Remington 1911 R1, or Sig Sauer P238? It's about .25 in diameter, and about .25 in long, the small shaft is about .125 diameter.

http://imgur.com/TfaEDNM

http://imgur.com/NmCOBRc

http://imgur.com/40aoCK8

I just took the plate off my 500 Magnum which exposed the trigger and all the internal stuff. Also took cylinder ejection mechanism apart.
Hope someone can help.
Thanks
Bruce