Re: Dont laugh at this question.
When you order a barrel, you'll be telling them the finish length (boltface to muzzle) you want, they're not concerned with your effective length (bullet base to muzzle).
The barrel will come in about an inch, inch and a half longer than specified so it can be finished at, or slightly longer than the specified length.
Effective length is also rarely refered to, chamber face to muzzle is. In other words, if someone tells you they have a 30" effective barrel length, and they're refering its overall length, boltface to muzzle, that would be highly unlikely, also inaccurate.
For comparisons and such, 99.999% of people are offering barrel length numbers based on muzzle to boltface, or muzzle to receiver face.
Muzzle to boltface is however the correct OAL, but about 1" longer than muzzle to receiver face, which is really a not too much of an issue.
Effective barrel length is most often used to determine the percentage of propellent burned, pressure at the muzzle, barrel time, load efficiency and such.