Barrel length?

[hkusp1]

How do you measure the length of a barrel on a already assembled rifle? is it measured before or after the chamber?

 

[double_r76]

From the closed breech face... and I quote!​

"The ATF procedure for measuring barrel length is to measure from the closed bolt (or breech-face) to
the furthermost end of the barrel or permanently attached muzzle device. Permanent methods of
attachment include full-fusion gas or electric steel-seam welding, high-temperature (1100°F) silver
soldering, or blind pinning with the pin head welded over. Barrels are measured by inserting a dowel rod
into the barrel until the rod stops against the bolt or breech-face. The rod is then marked at the
furthermost end of the barrel or permanently attached muzzle device, withdrawn from the barrel, and​

measured."

http://www.atf.gov/publications/download/p/atf-p-5320-8/atf-p-5320-8-chapter-2.pdf

-Randy