When I first started into the AR15 world, I had a strange desire to get an HBAR (Heavy Barrel). When I finally got myself one, I quickly saw the downside to it and learned why I didn't want one anymore. All it took was a few outings with the HBAR. It was pure misery.
I had also come to realize that the AR15 was originally designed to be lightweight. The original 20" AR15 sporters sold by Colt weighed in at around 7.6lbs loaded. The AR15 was never meant to be a machine gun or a sniper rifle originally.
Superlight barrel carbines point vert fast and balance the weapon much better than heavier AR15 barrels. Although many people who advocate HBAR's are quick to point out that thinner barrels heat up much faster, they tend to forget that they also cool down much faster.
Yes, you lose some accuracy, but not the practical kind in short-lived defensive shootouts.
I've gone through carbine classes where people's superlights (many LEO's) have held up just fine through all of the shooting drills even though we were putting a lot of rounds downrange quickly. I'm convinced that the superlight barrels are just fine for any likely scenario one might encounter as a civilian or an LEO.
This particular carbine that I built was inspired by a rifle my brother had built with a chrome lined superlight "pencil" barrel and a carbon fiber free floated handguard. This is the same guy that told me not to get the HBAR in the first place. However, some of us have to experience things the hard way before we learn...
We had done several builds (for me and helping others) and had so many leftover parts from past builds that I practically had enough to build another complete rifle. This happens as most AR15's we built were upgraded and utilize other various parts, leaving various extra parts. All I really needed was a barrel and the lower receiver.
I have since upgraded and changed out certain parts, including the buttstock, handguards (now DPMS carbon fiber free floated), and from an A2 fixed carry handle upper to a flat top upper with a cut down detachable carry handle.
It may not even have finished it's full transformation. I might even try to lighten it up even more with a Cavalry Arms complete AR15 lower, which I estimate may drop close to 1lbs from the total weight.
Although it is mine, I built this one with my wife in mind. She shoots it very well too. At one point I had considered getting her an M1 Carbine, but the Superlight AR15 is very light. On top of that, it shoots a better round that I already own, shoot, and reload for, and it has parts that are compatible with my other AR15 rifles.
It's a light and handy carbine that I can trust with my life and the life of my loved ones.