No, empty mag.
I have a Centurion Lightweight barrel right here waiting to be built up. The barrel under the handguard has a standard Lightweight profile: after the chamber swell it tapers down from .680" to .600" right before it flares up to the gas block soulder; I'm pretty sure this is a bit skinnier than a Noveske N4. In front of the gas block it is a straight .680". I intend to have the section in front of the gas block turned down to .600" (standard Lightweights are .575" here, but I want just a tad more beef in this area.) to turn it into a true Lightweight.
The Operator is a great barrel too:
http://i264.photobucket.com/albums/i...SPx4/ub3-5.jpg
In fact I prefer the Operator's profile to the Centurion midweight- the Operator has a tapering profile, while the Cent is just a straight .750" run, as you can see above in the OP. I forgot to weigh the Cent before it was installed, so I don't know which is heavier, but I'll bet the Cent is. No big deal though.