Why doesn't the cylinder length count in barrel length in a revolver? For that matter, why isn't chamber length deducted from a rifle's measurement? The bullet doesn't start from the breech face.
Bill
I believe I have found the source of my confusion.
There are two parties interested in barrel length.
The manufacturers and consumers in one camp and the regulators in another.
I was considering the BATFE method of measuring barrels. Their concern isn't ballistics, but conceal-ability.
One can simply drop a dowel down the barrel of an unloaded firearm, from the muzzle end until it contacts the closed bolt/slide. Measure that length of the dowel and you will have the barrel length.
This usually includes the chamber.
The revolver is measured the same way if it has revolving barrels like a pepperbox.
I assumed the BATFE would be consistant and rational in including the chamber as a part of barrel length as the cylinder length affects conceal-ability. Silly me. That's too rational.
If the revolver has a cylinder separate from the barrel, the cylinder is not included in the measurement.
Muzzle to breech face measurement is very rational for non-revolver manufacturers and consumers that are interested in balistics, parts ordering, aesthetics, sight radius, weight, balance, etc.
Imagine Winchester/Remington/Howa screwing various .30 caliber barrel blanks of the same length, into receivers. Then having to determine, and advertise the spectrum of barrel lengths if measured from the front of the chambers as they are cut. .308, .30-'06, .300 Win Mag, .300 Norma, .300 H&H, etc.