I can't tell ya who milled it but that thing is very cool.
The custom made matching bolt, jewel, milled front block, and so on make me believe a reasonably large operation was behind it though. That's not the kind of details normally seen on a cocker coming out of a small shop.
Any idea what type of feedneck threads it has? Angel threads could possibly mean it was based on an FBM body. Although that's unlike any FBM body I've seen.
The Facebook world figured it out. More accurately Tim Firpo figured it out. It's a Blizzard Cocker. They also done a Blizzard impy I believe is what Tim said. So believe it or not it comes from a fairly small shop that obviously isn't around anymore.