I recently came into possession of four of these barrels. I had wanted to use them on my own rifles, but for time and money reasons that just isn't going to happen.
They are carbine port, heavy under the handguards. They have an M4 cut that is located somewhat forward of the conventional position, and stripped FSBs (no sight) that are straight pinned on. The muzzles are threaded and the barrels are finished in some kind of black bake on. They have a few handling marks, but are brand spanking new. Chambers are .223 Wylde and will work with 5.56 NATO. Twist is 1/7.
I'm going to need to get $320 plus $15 for shipping each. If you want the whole set I'll go shipped for $1200.