Uberti and others make a model 1876 repro chambered in several ctgs. the .45/60 (1.9"), .45/75 (1.9") and .50/95 (1.9"). I have the .50/95 while my bro has the .45/60.
I could easily trim the brass to 1.8" (but usually to 1.85").
My rifle runs 368gr. cast at 1,650fps.
My bro's rifle puts 340gr. out at close to the same vel. using 3031 powder, seems to me.