Hi There,
What you have is a New Model No: 3 Double Action, First Model.
These were first offered in .44 S&W Russian but later, a
"Frontier" model was added that chambered for the .44 WCF
(i.e. .44-40). The difference was the length of the cylinder.
Most .44 Russians have a 1-7/16" long cylinder and the "Fron-
tier" had a 1-9/16" long cylinder.
The Frontier wasn't a good seller and some of them were given
new cylinders in .44 Russian to fill sales so keep this in mind
when determining caliber.
Cheers!
Webb