In article et, "Evan
Williams" wrote:

Just in case you aren't confused yet, here's some more trivia. Cartridges
such as 44/40 and 45/70 come from the old black powder days. The second
part after the slash denotes how much powder was inside the casing and that
gives you the size of the casing. It sometimes helps to know the history of
the round.

If you aren't confused yet, and want even more...
the "44/40" (sic) is actually the .44-40 also originally called the .44 WCF ,
for Winchester Center Fire, but when other companies started chambering
weapons for the .44WCF they didn't want to use Winchester's name, so they
called it the .44-40 for the 40 grains of FFFg black powder in the case.
And even more confusing, the old cases were thin and had "balloon" heads,
newer cases developed in IIRC the '20s or '30s had thicker walls and a solid
head and will accept maybe 35 grains of powder, so it's not even a .44-40
anymore.

Similar story with the .45-70. First released in 1873 for the trapdoor
Springfield, was called the .45 US Gov't, then popularly renamed the .45-70.
There were 2 loads for the rifle, one used a 405 grain bullet, the other a
500 grain bullet. Then there was a load for the carbine that the cavalry
carried that used the 405 grain bullet but a reduced load of powder with
only 60 grains, but still called the .45-70.

Not to mention the .38 WCF also called the .38-40 which is the .44-40
necked down, not to .38, but to .40. So it really ought to be called the
..40 WCF or .40-40, but I guess Winchester had some Marketing issue
with the name of that one, so despite the fact that it's a 40 caliber they
called it a .38

1860 through 1930 was a fascinating and fast moving time in the arms
industry.

--
Harry Andreas
Engineering raconteur