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Thank you Mainspring, appreciate your comments. You are correct, the dimensions for lands and grooves are reversed, thanks for pointing that out.
The rifle I have is a mishmash of parts, I think I will post some pics of it and solicit some help identifying it.

Hoping that someone with a lot more knowledge on Rolling Blocks can help me with this question.
Have a mystery Danish/Greek? Rolling Block and finally got around to chamber-casting (my first) with Cerrosafe.
After the obligatory one-hour cooling period I took the following measurements and I'm no ...