Ruger GP100 Pin

[HangEmHigh]

I was cleaning my Ruger GP100 after getting back from shooting last weekend and noticed that a pin was sticking out from under the rear adjustable sight. The pin is very small and runs through the backstrap under the sight. It was already out about a 1/4 inch so I pulled it out the rest of the way so that I wouldnt lose it. It doest seem to be a tappered pin and I cant see any detent. Any ideas how to re-attach?

 

[kendall-op]

Not sure about put back, but on ruger web page they have part list that might help.