I recently acquired this A2 HBAR barrel.  Was just wondering what you guys could tell me about it.
Some things I noticed is the stamping front of the FSB is "C MP 5.56 NATO 1/7 HBAR".
There is no other stampings that I can find.  It does have a couple of areas where it appears something was attached to the barrel?
The finish is rubbed off in these areas.  One is front of the FSB and has almost rubbed off the "1" in the 1/7 stamp.  The other area
is just behind the contour under the hand guard.  I have no idea what sort of attachment would do this?  
I can get the barrel refinished with no issues.  I was wondering if this would be a military barrel and if so, what years this barrel might be from?

I was considering using this for my Cold Model 741 clone build.  But was not sure if it were the right contour?

Thanks

Yep, there sure is.  Some deformed teeth and a damage to the delta ring.
What puzzles me is that the FSB does not have a bayonet lug?  I would
not have thought a military rifle would have a neutered FSB?

Looks like a standard Colt 6601 barrel. The came in several variations, threaded with bayonet lug, threaded without bayonet lug, and non-threaded without bayonet lug. The variations depended on when it was made, pre ban, ban era, or post ban.
Good barrels.

It is not a military barrel, but off of a Colt civilian rifle.


Adco Firearms can repark the barrel, and re-contour it for you as well.

He's right, it's a ban-era Colt commercial barrel. Check for a date behind the FSB, and it might also have a "G" near the breech since Colt got some of their barrels from Green Mountain. I have one of those.

I have a guess for those wear marks near the muzzle: They're from a lathe steadyrest. I bet the muzzle was originally crowned and someone threaded it on the aftermarket. The marks at the midpoint are probably barrel vise. The gunsmith who worked on this wasn't terribly careful.

Looking at it a little closer, it is a ban era 6601 barrel that originally was sold sans bayonet lug, and bare muzzle. It was threaded later in its life.
You can tell it was originally a bare muzzle because it does not have the 'step' before the threads.

Jkirk nailed it--Colt commercial neutered barrel that was later threaded.  Just looking at the barrel extension, barrel hardly been shot.  I'd send it to John Thomas at http://www.retroarmsworks.com/ to re-park.  He does excellent work and much faster turn around than Adco.

+1 on what he said
(I have the same exact barrel)

btw all Match Target barrels had the chromed chamber but only a few had a chromed bore. Mine made in April 2000 is fully chrome lined.
some 6601 barrels even came with a F marked FSB (a friend on mine has one, made in 1999 iirc) and they zero just fine.
also, near the HG cap there should be the manufacture date (mm/yy)

Mine's from 2008 and I don't think any part of it is chromed.