Colt AR-15 A3 6721 Tactical Carbine 5.56/.223 16″ Semi-Auto Rifle HBAR

SOLD FOR: $1,125.00

LSB#: LSB260502PB001

Make: Colt

Model: AR-15 A3 6721 Tactical Carbine 

Serial Number: LBD022453

Year of Manufacture: Ca.1994-2004 / Modern

Caliber: 5.56 NATO / .223

Action Type:  Semi-Automatic, Direct Impingement, fed by detachable magazine

Markings:  The left side of the receiver is marked with the Colt Rampant logo and “COLT” / “AR-15A3” / “TACTICAL” / “CARBINE” / “CAL. .223” / “SER. LBD 022453”, “COLT DEFENSE” / “HARTFORD. CONN.” / “0-U.S.A.-”, “SAFE FIRE”.  The right side of the receiver is marked “RESTRICTED” / “MILITARY/GOVERNMENT” / “LAW ENFORCEMENT/EXPORT” / “USE ONLY”.  The barrel is marked “C MP 5.56 NATO 1/9 HBAR”.  The front of the picatinny rail is marked “M4”. The left side of the Bolt Carrier is marked with a “C”.  

Barrel Length: 16”, 17.25” overall with A2 Flash Hider.  HBAR. 

Sights / Optics: The front sight is an A2-style post and the rear sight is an A2 style detachable carry handle mounted to the flat top picatinny rail above the receiver. The carry handle is removable revealing the picatinny rail.   

Stock Configuration & Condition: The handguard is a carbine length round ribbed polymer handguard with sling ring below the gas block and bayonet lug. The pistol grip is a standard A2 AR-15 polymer pistol grip with checkering and serrations. The buttstock is an M4 waffle style 4 position collapsible buttstock with sling slot and sling swivel. The buttplate is integral to the buttstock and checkered. There is scattered handling wear and scuffs. The checkering remains defined. The LOP measures 13.25” from the front of the trigger to the back of the fully extended buttstock. Overall, the stock rates in about Very Good-Fine overall condition.  

Magazine Quantity & Condition: 1x 20-round Colt Magazine and 1x 30-round Colt magazine. The magazines show moderate operational wear and remain in Very Good condition.

Type of Finish: Matte Black Hardcoat

Finish Originality: Original

Bore Condition: The bore is bright and the rifling is sharp. There is no visible erosion in the bore. In this writer’s opinion, the bore rates about 9/10.

Overall Condition: This rifle retains about 97% of its metal finish. There are handling marks scuffs throughout. The screw heads are sharp and pins are unmarred. The markings are clear. Overall, this rifle rates in about Fine condition. 

Mechanics:  The action functions correctly. We did not fire this rifle. As with all used firearms, a thorough cleaning may be necessary to meet your maintenance requirements.

Box, Paperwork & Accessories: Paperwork, cleaning rod and brushes, nylon sling, and serial matching factory box.   

Our Assessment:  The Colt AR-15A3 Tactical Carbine Model 6721 was developed as a heavy-barreled, semi-automatic carbine for law-enforcement, government, and civilian use. Built around Colt’s direct-impingement AR-15 system, the 6721 paired a 16″ HBAR-profile barrel with a flat-top upper receiver, detachable A2 carry handle, fixed front sight base, and collapsible stock. Its 1:9″ rifling twist was intended to stabilize a broad range of commonly available .223 Remington and 5.56 NATO projectiles, while the heavy barrel offered greater resistance to heat and reduced barrel movement during sustained firing. Examples marked “RESTRICTED MILITARY/GOVERNMENT LAW ENFORCEMENT/EXPORT USE ONLY” were produced during the 1994-2004 Federal Assault Weapons Ban era and are recognizable artifacts of that period in American firearms regulation and Colt commercial production. The 6721 remains desirable among Colt collectors for its factory HBAR configuration, law-enforcement markings, and traditional carbine features.

This Colt Model 6721 retains approximately 97% of its original matte-black finish, with scattered handling marks and scuffs but clear markings, sharp screw heads, and unmarred pins. The bright 9/10 bore retains sharp rifling, and the action functions correctly. Its Colt-marked bolt carrier, 16″ HBAR barrel, detachable carry handle, four-position stock, bayonet lug, flash hider, and two Colt magazines provide a classic factory tactical-carbine configuration. The included paperwork, cleaning accessories, sling, and serial-matching factory box further enhance this rifle’s completeness and collector appeal. Please see our photos for a better understanding of the condition and good luck with your bids! -MY