Xausa,

Not sure if this helps but I saw an identical mount to the one on your rifle on a rifle being built by my friend Dave Norin some years ago. I can't remember who he said made the mount for him, but I'm guessing that there can't be all that many people who make this kind of mount? Maybe you could e-mail Dave a link to this thread or send him the pics and ask. Once you know who made the mounts, it may be easier to find out who it was? Again, I don't think there are all that many rifles built with this kind of classic slide on - slide off mount?

Beautiful rifle! Congratulations!