This is an exerpt from a book report I wrote for THE SHOOTIST a few years back on THE HISTORY OF WINCHESTER FIREARMS. The key passage is the paragraph quoting directly from page 12. of the book;
Review; THE HISTORY OF WINCHESTER FIREARMS
By; Duncan Barnes, George R. Watrous, James C. Rikhoff, Thomas H. Hall, and Pete Kuhlhoff, Winchester Press, 5th edition 1966, 1973, 1980
ISBN 0-8329-0397-3
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""Now; Let’s get down to brass, “tacks” I was going to say. What about the Henry center fire cartridge?
Frank Barnes was likely misled by the 1895 Winchester catalogue. It clearly stated that the manufacture of the model 1866 was abandoned as soon as manufacture of the model of 1873 commenced. I was surprised to read that manufacture of the model of 1866 continued on a sporadic basis until 1898. The record of the last 1866 firearm assembled bears the date August 1898. I have personally seen an original 1866 in .38 cf, special, I think. It was used in a match in Victoria some few years ago by a shooter from Washington State. Apparently it had been assembled on a special order basis in 1918 from parts discovered in the plant.
Page 12. “In 1891, 1,020 M/66 components parts on hand for many years, were used in the assembly of rifles chambered for the 44 “Henry” center fire cartridge and shipped to a firm in Brazil. In making up this lot of guns it was necessary to change the breech pin by discarding the Breech Pin Snapper, substituting a center fire firing pin and also inserting a threaded bushing in the face of the breech pin base with a hole in the center to allow the point of the firing pin to protrude and hit the primer. All other components were the same as previously used on the standard M/66, 44 caliber rim fire rifles, except for the chambering of the barrel.”
This appears to solve the mystery of the 44 Henry center fire. I am sure that some .44 rim fire firearms were locally converted to center fire. If the 1,020 originals were shipped to Brazil, most examples found in North America would likely be of the locally adapted variety. Ammunition would not likely be a problem as long as .44 American ammunition was available.""
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Of course, we now know the Brazilian part of the story!