I haven't been on here in a longtime.  I am very rural and out of the loop.  I acquired a strange upper Saturday.  It is a bit of an oddity in my book, a 16" HBAR????  The Upper looks to be factory assembled with very little use.

The details are a Colt flattop M4 (above the gas tube) upper receiver with round forward assist, C and Keyhole marked with a Cardinal Forge Carry Handle.

The barrel is a 16 inch HBAR marked C MP 5.56 NATO 1/9 HBAR with an A2 Flash hider and F marked Front Sight Base with Bayonet Lug and Sling Swivel.  It has glossy handguards just regular not the big Oval style.

To me it seems an impractical configuration as it sits, a 16" HBAR.  Who would want that and what for?  It looks like a great bunch of parts to me.  If I keep it I think it would make a great SBR cut off @ 10.3 or 11.5 inches.  I would have to look into the gas port sizing if I went that route and see if it is even worth doing.

I may try to sell it intact or may possibly remove the barrel and sell it that way.  Or SBR it.  What do you guys think.  What kind of value is it, being in very lightly used condition with no BCG or Charging Handle?

There's nothing odd about it.  It's a Colt 6721 AR-15 A3 Tactical Carbine.  It's the most accurate off-the-shelf chrome-lined NATO chambered barrel that Colt has ever produced.  They're a nice barrel for a RECCE configuration.














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Back in the early 90's , HBAR AR-15s were all the "Hot Thing!"

It was HBAR this &  HBAR that.

HBAR EVERYTHING!!!

People believed HBAR was best because of "Accuracy" and for "Heat Dispersion".  Pencil barrels were considered "old" & "gross"

And 1/9 twist?  Cutting edge to use that bad ass M855 greentip.

Bigger_Hammer

Wow, thanks!  I still like my other 16 inch upper.  It is a used USGI M16A1 upper with the old slip ring and a 16 inch 1/7 twist pencil barrel with an A1 Flash hider on it.

HBARs are tack drivers, and groups don't start widening when they heat up. Impractical? Not if you like accuracy that stays accurate.

I had one of those back in the day and it was an absolute hammer. It was one of the most accurate practical weight AR's I've ever shot.  I foolishly traded it for a 6920, this taught me never to sell/trade a gun that I like for another one that I think I'll like more.

You got to get out and actually shoot more.

Yeah, I would take a 6721 barrel all day over a 6920.  

Also the same barrel could have come from a 6731, which was just the fixed stock version of the 6721.

The 6731 also lacked the threaded muzzle and bayo lug