5.56 Timeline

Colt Lightweight AR6720 Carbine

This is my (very short) opinion on the Colt AR6720 Lightweight LE Carbine.

I constantly have people asking my opinion of what basic AR type rifle is best for them, to use for home defense and/or duty or patrol rifle use. ” Should I get a Colt or equivalent M4 type carbine?” Many who ask me these questions are my current coworkers, officers I have worked with in law enforcement and people I have trained or train with. One thing we can all agree on at Loose Rounds is Colt is the way to go when looking for a duty AR15 type carbine. Whether you want a plinker, a hard use training, home defense or duty carbine, the Colt AR15-A4 Lightweight LE Carbine is one of the best. As with all Colt rifles, you know you are getting the  (“Mil-Spec”) features and HPT/MPI testing of the important individual parts in the 6720.

Colt AR-15A4 Lightweight LE Carbine
Colt AR-15A4 Lightweight LE Carbine

I have used several variants of the AR15 platform for duty use in semi auto and full auto versions. These range from; The standard Colt M4 14.5″ Carbine (LE6921/ RO977), LE 16″ Carbine (LE6920), 11.5″ Commando (LE6933/R0933) and Government Carbine (AR6520). When I look at an all around purpose carbine, that can fill multiple roles, I think of the Colt AR6720. The Colt AR6720 has been out since 2009 and was a request by a distributor (Clydes) for Colt to update the 6520 Government Carbine. It is basically a 6520 Gov. Carbine (LW Gov barrel) with an M4 marked flat top upper with M4 feed ramps.

Colt AR6720 Light weight LE Carbine
Colt AR6720 Lightweight LE Carbine

The AR6720, in my opinion, is the best all around performer in the AR15 carbine patrol setting. You have the reliability, accuracy, and modularity you have come to expect from the AR15 platform. For me the AR6720 seams to handle just right. The handling and transitions in movement of the 6720 are awesome.  The carbine seams to be a seamless extension of your arms and fingers. It is a joy to shoot. It is the most well balanced, fast and easy handling  16″ AR I have used.  For me, handles like the familiar 11.5″ commando, just with a longer barrel.  The stock weight comes in right at 6.12 lbs. With the (MIL-B-11595E CMV) Chrome Lined 1/7 twist barrel in 5.56mm, it will handle any ammo you want to put down range.  If you choose the right accessories and enhancements, you will not add to much to the weight. I have owned numerous AR carbines and the 6720 is one of my favorites. It just might be my favorite.

The only complaint, some people may have, is the 6720 does not have an “F” marked FSB. This is a non-issue. The FSB comes with a taller front sight post, making up for the lower shelf on the FSB, for zeroing with any BUIS you choose.

Barrel / FSB /FSP
Barrel / FSB /FSP

I have chosen to set my 6720 up, in the following configuration, per my personal preferences.  With a loaded 30 round magazine, I am still within the 6 lbs. range. This maximizes performance and handling of my patrol carbine needs out to 200 yards, although the Colt AR6720 is very capable of excellent performance well past 200.

  • Tango Down Battle Grip
  • Daniel Defense Omega 7 Rail
  • BCM Gunfighter Charging Handle (Mod4)
  • Aimpoint Micro w/ADM mount
  • Tactical Link Z-360 mount and Convertible Sling
  • Lancer L5 Translucent AWM magazine
Colt 6720 w/ DD Omega 7 rail, Aimpoint Micro
Colt 6720 w/ DD Omega 7 rail, Aimpoint Micro

At current prices, you can find the AR6720 in the 800 dollar range. I feel there is no argument or justification you can make, if your in the marked for a serious lightweight Defensive/Duty carbine, to buy another carbine at these prices. For a basic AR carbine, the Colt AR6720 is probably the best lightweight carbine purchase you can make. There are numerous articles on the accuracy of the 6720 and we have shown you how accurate a Colt carbine can be here on Loose Rounds. The 6720 is fast and smooth, and it will make the hits when it counts. If I was still patrolling on the street, the Colt AR6720 would be in my cruiser and it would be my go to patrol carbine.


Here is a good video with more info and shooting, by Mrgunsngear, on the AR6720:

A few thoughts on the M16A4.

The FN M16A4 I carried in Iraq.

When I enlisted in the USMC I was issued a M16A2. Other then when we occasionally added a PEQ-2 IR laser, a flashlight, or the issued M203 grenade launcher, we felt this gun did everything we needed it to do.

We didn’t know about things like quad rails and quick detach accessories. Those introduced a whole different mentality to how to use our weapons.

When the M16/M16A1 become the M16A2 it gained about a pound. From the M16A2 to the M16A4 it gained about another pound. Most of this comes from the Knights Armament Corp. (KAC) M5 RAS rail system. The KAC M5 RAS is a good rail system, but it has been surpassed by much lighter better free float rails.

That additional weight, combined with the weight of various lights, lasers, and optics along with the fixed stock not playing well with our body armor made using the M16A4 a great deal more awkward. There was a huge difference between just wearing ALICE gear and shooting a M16A2 verses wearing an Interceptor vest with plates and MOLLE II gear shooting a M16A4 with ACOG, PEQ-2, and a Surefire.

My Colt AR15A4 with Trijicon TA31RCO-A4

Since I got out of the military, I have owned several rifles similar to the M16A4. I had a Bushmaster, a BCM, Saber, and now a Colt AR15A4. Most of these guns I shot for a while then got rid of. The reason for that is that the M16A4 is not particularly special at anything.

I have often told people that the M4 is a jack of all trade, but master of none. Truthfully, the M4 really excels at many of the roles it is used in. The M16A4 type rifle falls into an odd place where it doesn’t particularly do any one thing significantly better than the M4, yet is inferior in handling and weight.

The M16A4 is not a precision rifle. While it is more than accurate enough for combat, it is not a sniper rifle. If your planning to shoot in Rifle Competition, you would be better off with a rifle with a fixed carry handle with match sights, and a free floating match barrel.

While the M16A4 isn’t overly large or heavy, it certainly is not as handy for shooting indoors or confined spaces. The M4 and smaller guns show distinct superiority in handling while in close quarters shooting conditions.

While I was in the Corps we were generally of the belief that the M16A2/A4 was a superior weapon system to the M4. Statements of increased accuracy, reliability, and lethality (due to increased muzzle velocity) were occasionally thrown around.

When using Iron sights, the longer sight radius of the M16 is clearly apparent over the carbine. However most of us no longer use iron sights as our primary way to aim, so this is a moot point. As for mechanical accuracy, the M4 doesn’t give anything up to the M16.

Around 2005-2008 or so I often recall reading on the major gun forums that the AR15 rifle is so very much more reliable than the Carbine. We do know that the rifle has lower gas port pressure and should be easier on components than the carbine. Still for most users they will not see a reliability benefit from the rifle. Not to mention the carbine is clearly reliable enough for groups like the SEALs, U.S. Army, and various foreign special forces groups. So back in 2006, the M4 was good enough for the US SEALs, but not a good enough weapon for the USMC infantry.

While I was in there was a push to give the Marine Infantry M4 carbines. This was considered foolish. Later after I was out there was a push to make a “Product Improved” M16A4 with features like a free floating rail, and a compressible stock. I have heard that from several sources that the USMC decided instead to just give infantry Marines M4 carbines. In 2007, shortly before I got out, one of the other unit got brand new M4 carbines. When I inquired why, I was told that one of John McCain’s son was in that unit. I don’t know if that is true, but it sure seems like the type of reason one unit would get superior equipment. Clearly the M4 is good enough for the USMC now.

I like the M16A4 configuration, but I own one more for plinking and nostalgia. I firmly believe that the majority of AR15 user would be better off with a good carbine than the M16A4 configuration.

Trijicon SRS lens glare/reflection

A common complaint about the Trijicon SRS is a reflection of the circuitry that appears when the optic is turned towards the sun.  We experienced this on a recent range trip and snapped a photo to give everyone an idea of what users are talking about when they reference the issue.

Very distracting and quite easy to lose the dot, which was indeed on in this pic.



Can’t say I’m a fan.  I’ll be sticking with my Aimpoints.