Did you find it Tom?
I'm doing some similar reaserch, but my books I need are at work. Looking at putting a .450NE in a steve Earle falling block. Might have to modify the extractor. It seems a bit overly robust. It looks like as it is I have .138", a .544" baseon the .450 from the extractor cut which is .400" from center of bore. I'm think about thinning the extractor a bit. More reaserch needed.
Steve


Firearms imports, consignments


[Linked Image from i.imgur.com]