I do not recall where I got my Metcalfe block - and that is odd, because I normally DO remember such things. I think it came from a private party in the midwest, about 1990.

I'd passed on one locally, for $2000, as being just TOO much. I was planning to make one also, until I blundered into the real thing. IIRC, think I paid $1000, and my wrapper has been opened! The more expensive one was sealed, and the wrapper was more legible.

Those are the only two I've encountered, but I do not do the big shows. They ARE quite rare.

I was only willing to pay for the block because I'd acquired my rifle rather cheaply, A good friend found the stock at a garage sale, and I'd also gotten a deal on the device, just as a curiosity. A spare lockplate was very carefully machined and cannot be distinguished from arsenal work, but when my collection is disbursed, the gun will be permanently ID'ed as a modern reassembly.

My email address is on my profile.