Shrapnel,
On the WACA Forum a Well known Member Chuck, claimed in a past post that a small number of Center Fire Cartridges were made on the Later Model 1866 Winchester!
The 44-40 also referred to or known as .44 Win, .44 WCF, .44 Largo, (Spanish), mainly in Conversation when the "73' comes up.
So I'm a little curious and would like to know the real answer, as the Blue Book of Gun Values , lists the 1866 as .44 rim fire, and center fire also.
They've had errant info before so I won't say this is gospel!
HS58