Many thanks Ken, for this great tip.
I'm currently building another S. Hawken rifle, and once I had the breech in, and the tang soldered to the breech, I turned it over to see it the tang was in alignment with the bore, and found it bent to the left, or lock side. I made a set of three of these gizzmos, and was able to straighten out the tang very very easily. This device is a great addition to the gun builder's bench. Thanks again.