It could even be a 44 Russian ......

The 44-40 is a tapered almost necked like a 38-40 .

Then there's a straight cased 44 .... I want to say Colts that was a CF version of the Henry RF and used a .440 heeled bullet , think 22 LR for a visual . This one will be drilled straight through at about .440-.444 .

The Russian had the .440 case but used the now standard .426 dia bullet as they wanted an inside lubed bullet vs the heeled bullet outside lubed type . This one will have a straight case with a throat step . I don't when off hand the Russian came about .