John, You are quite welcome!
That article by Jack Lott is what ultimately led me to acquiring my Jeffery .577 3 1/4" made in 1896.
While it is a BP Express it still packs a punch (on both ends) at 6 1/2 Drams and a 650 grain bullet.
As you note, there is, to me, an undeniable romance to the Jones underlever hammer rifle.
Cheers, Mike