OMG!
i just read the ending of jch364's post about the pins being worn... Then I realized something... When I removed the master link, I remember looking at the pins and seeing something funky, but didn't pay much attention to it since I didn't really know what I was looking for. Well guess what the pins look like? I'll let the picture tell all...
These pins were grinded off on the top (rivet side) and then pushed through with a chain riverter. Gave me a hard time to remove once loose, now I know why...