After the fact, I had to modify it a little. The fit was so tight that I could not get it in the hole and the far rail at the same time. It drove me crazy. I finally tapped it almost all the way in, just enough sticking out to find the pin hole. Once I got both, I tapped it home with a drill bit. Works great now.5th question down the list,,, but I double check it atfer I mount it on the rail, they tap down pretty easy