You got yourself quite a project. I've seen several missing the front sight. There was a thread on the S&W Forum on a particular 1907 that was missing the front sight and the OP found one although he didn't say where he got it from. I'm no gunsmith so I can't answer your question about it being safe to shoot. I have a 1907 that I showed in a thread in this forum that I've shot and I was thoroughly impressed with it. Good luck with the restoration and keep the thread updated with your progress.
Bookmarks