Revolver barrel length measurement

[stevo]

I know on rifles, shotguns, and semi-automatic handguns the barrel length is measured from the end of the barrel to the breach face, usually by using a wooden dowel. How are revolvers measured? Is it the cylinder considered part of the barrel length. basically measuring from the muzzle through the cylinder to the breach face on the frame?

I have googled it and read different stuff, just want to hear opinions here.

Stevo

[BradM]

Cylinder is not part of the barrel.