1) if the flash suppressor is permanently attached (welded for sure, possibly certain kinds of staked/pinned, I'm not sure on that) it is legally 16"
2)the measurement is from the breach face (bolt).
From a ballistics perspective (energy) its a 10" barrel though. I'd be most upset that the actual "barrel" wasn't the 16" I paid for, assuming it was t your screw up for ordering the wrong thing.
Last edited by Brian Pfleuger; June 14, 2013 at 11:52 AM.