Winchester Mod 1866

A friend of me owns a Winchester Mod 1866. It is an delivery contract for Brazil.
The caliber mention on the barrel is 44B.

He want to know wich cartridges they used for this rifle.
The standart 44-40 or something else.
What does the B stand for ??

Someone has a box label of the 44B cartridges.


Hello Leon,
I believe these winchester carbines were chambered in 44 brazilian nagant.

Is .44 Brazilian Nagant a rimfire?

The Winchester Model 1866 Carbines made for Brazil were
in .44 Henry Centerfire Caliber. The meaning of the “B” in
the caliber marking is uncertain, but it is presumed to stand
for “Brazil.” At least one of these carbines was in 165,000 serial
number range, which would put it in the production-year range of
1886 to 1888.

Some additional information here:

Finding A little more time, I check a better source in my library for
the Brazilian .44 Henry CF carbines, and they list the serial number
range of these carbines as being in the 167,000 series, rather than

There were other centerfire conversions in the Model 1866, differing
in mechanical details from the ones sent to Brazil.

John Moss

Thanks for the info so far.
Gun is centerfire and serial number is 168XXX

Are there cartridges known loaded by Winchester ?


My understanding, unguaranteed, is that the 44 Henry cf and the 44 (or 440) Nagant cartridge are similar enough to work interchangeably. I think the Brazilians bought these intending to use them with the Nagant ammunition they were already using in the handguns.

Here are the Winchester .44 CF Henry. I did not have a Nagant to compare them to.


below a picture of a .44 Brazilian Nagant:

1 Like

Hi all

Hope you can find these pictures interesting, there are 44 Henry CF for carabiner and 440 Brazil Nagant for revolvers. They are in fact the same cartridge.
As far as I know the first 4 units from left to right are 44 Henry flat CF while the others are 440N.



I was doing some research (not on this subject) in the Winchester files at the McCracken Research Library in Cody, WY, a few years ago. I came across some in-house correspondence concerning the order for 1,000 44 center fire 1866 carbines for Brazil. It was mentioned that Brazil wanted these in .44 S&W American, but Winchester did not want to designate this name for the cartridge, so they thought they might call it .44 CF Henry Flat. But more importantly, the order number was mentioned. If you research Winchesters, you know that the letter gives you the order number your gun was shipped on, but there is no longer a record of those order numbers, so they are usually of little interest. Knowing the order number of the Brazil order, I asked Jessie Bennet to find what was shipped on that order. It was a pain, but she agreed to do it. Finally, she found 999 of the Brazilian guns. A couple months later, she found the last one, which was way out of serial number range of the other 999. So, now you can request a search on your serial number, and Jessie can confirm if it was or was not on the order for 1,000 to Brazil. On a visit with some collectors in Buenos Aires, I brought up the subject of what the cartridge boxes on the Brazil order looked like. I was told that even the Brazilian collectors were not sure, but the general opinion was they were pretty much unmarked pasteboard boxes.


Thanks all for your input on my request to find answers for the 44B round.