One old:
Metallic Cartridge Nomenclature
and one from the latest Handloader:
There Are No .32, .38 or .44 Calibers

When I first got into shooting I was bewildered by all the cartridge names
and the fact that many times they don't accurately describe much of anything.
This is probably a universal symptom.
I read "Cartridges Of The World" several times.
Then I got other reference books, some about cartridge conversion where the dimensions are super important.
Slowly I learned the basics of the families I was interested in especially revolver rounds, the 44 in particular.
The above articles have some cool historical background some of which I never read before.
Recommended.

__________________
NEMO
"Everything 44"

All that stuff is fun .38-40 is actually .40, a .36 Navy is a .38 but a .38 special is almost a .36, a .41 Long Colt (depending on how you measure) is .38ish and on and on a 56-56 Spencer is neither .56 caliber nor 56 grains of black powder. The new 56-50 Spencers are .51 caliber ah well.

I like the part where the only true 44 may be the 44 Colt.
You can see where the current .429-.430" 44 comes from as it is the heel dimension of that round.
Comparing heeled and modern style inside lubed bullets is in itself somewhat misleading
as the relationship between the bore and cartridge dimensions is different in those 2 cases.

Another of the few cartridges that understates the bullet diameter is the 450/400NE 3" (.400 Jeffery NE)
which is actually a .41 and can fire .41 magnum bullets in reduced loads.
One of my "grail" guns:

Attached Images

	Jeffery 400.jpg (289.0 KB, 20 views)
	Jeffery 400 b.jpg (215.1 KB, 21 views)

__________________
NEMO
"Everything 44"