I contacted the original owner and got more info. It was built to order for him. But this is the info from the spec sheet:

- 16" 5.56mm caliber barrel, threaded the standard 1/2 x 28, A2 flash hider with the correct crush washer
- forged A2 front sight base with bayonet lug (not the cheaper cast front sight base).
- Chrome-moly, high vanadium steel and hardened to a U.S. government Mil-spec of Rc 26-32.
- Manganese phosphate finished IAW 5.3.1.2 of Mil-STD-171
- Mil-spec M4 contour (.750 under the front sight base) complete with the M203 groove in the front.
- Button rifled with 6 grooves, right hand, 1 / 9" twist.
- FORGED A3 upper receiver with built in Mil-spec M1913 Picatinny accessory rail, made from certified 7075T6.511 alloy forgings, hardcoat anodized IAW Mil Spec A8625, Type III, Class II, black per No. 37038, Table IX with nickel acetate seal, as per the Mil-spec

Any feedback on this barrel based on the info above?