So, if we have two different firing pin tip diameters for the Hepburn, an early one initially designed and used with black powder, and a later revised one for smokeless, just what are the two different diameters so we can actually distinguish between the standard action and the high-power?

And are these two different firing pin tip diameters also match with those used in the black powder and the revised high-power rolling block actions?

I was referred to Tom Rowe from another site, and it turns out we don't live that far apart.  I visited Tom this week and took the rifle along.   He verified that my rifle is a rare variety known as a High Power, available in several smokeless powder calibers.  However, Tom has only found two of these rifles to date, one of which is mine, and both in .30-40.  My rifle has two special order features: shotgun butt, a $2.00 upgrade, and a checkered fore end.  Tom estimates that only about 25 High Powers were built.  Tom is writing a book on Hepburns and my rifle will be featured in his book.    I bought a correct rear sight taken from another Hepburn and I'll be shooting the rifle as soon as the sight arrives.  I'm only going to use lead bullets at this juncture, although the ordnance steel barrel was designed for jacketed bullets.   I really fell into a nice find on this rifle.

Outstanding news and one could only imagine the conversations you had while visiting Tom, another special event included into the rifle purchase.

J.Louis