Re: 1873 Winchester
The value is determined by two things; (1) The graded condition, and (2) the specific configuration of the gun. In order to assess either, I will need to see several clear detailed pictures of the gun. It could be a $700 "beater" parts gun, or it could potentially be worth $10K+.
It is an 1885 vintage gun, and the cartridge is the 38 W.C.F. If the rifle is in good mechanical condition, it can safely handle any modern factory loaded 38-40 ammo.
Real Men own and shoot a Winchester SINGLE-SHOT!