end of the bbl (muzzle end) not including Flash Hider down to the bolt face (closed).
Posted: 4/27/2003 4:35:17 AM EDT
[#2]
US BATF measures the barrel [i]with a rod down the bore[/i] to the face of a closed, cocked bolt. Length includes all [i]permanent[/i] muzzle devices, which is how a 14.5" M4 barrel plus permantly mounted Vortex gets out to the 16" required by NFA34.
