Lightweight AR-15 Upper

I have built several lightweight AR's. In my opinion, a 6.5lb AR is the ideal weight for the platform (any heavier, you can get a larger caliber). I have noticed no difference in accuracy in a pencil barrel vs M4 profile. Yes, the pencil will heat up faster, but unless your doing several mag dumps within a short span of time (which would be dumb anyway) there are no drawbacks whatsoever to the weight savings. Go for a 16" pencil barrel, skip the 14.5, no point. The MOE handguard works great. After your first lightweight build, you will wonder why the HBAR or m4 profiles still even exist on the civilian market.

I assembled my lightweight carbine, using Daniel Defense upper and lower receiver, BCG, 16" lightweight barrel and Troy Xtreme TRX free float handguard. It is very light.

I do not feel that going through the trouble to get a 14.5" barrel and then permanently mount a flash hider give that much weight advantage over a 16" light weight barrel.

The Troy handguard is very light and doesn't need the delta ring that is required with a standard handguard.



Most of the weight saving is in the red dot sight. I use the Aimpoint H-1 with an Israeli made mount. The H-1 is a whole lot lighter than the larger Aimpoint Comp M4. The Streamlight TL3 is also very light. The back up iron sights are Daniel Defense.

With Vickers sling and Vltor stock (not the Magpul stock in the picture), 7.0 lb. This is light. My girlfriend and other female friends love to shoot this carbine.

Resist the temptation to hang heavy stuff on it. A stripped down M4 carbine with the actual M4 profile barrel is light. It's the heavy optics, huge weapon light, vertical grip and other stuff that make the rifle heavy.

The Magpul handguard is lightweight, and looks cool. I've been thinking about swapping out my standard handguards for one on my lightweight, but haven't bothered since I'm more worried about getting parts for my 6.8 build.

I used a 16" lightweight barrel, standard flash hider, standard A2 upper. My rifle weighs just a bit over 6#.

Jackal said:

I have built several lightweight AR's. In my opinion, a 6.5lb AR is the ideal weight for the platform (any heavier, you can get a larger caliber). I have noticed no difference in accuracy in a pencil barrel vs M4 profile. Yes, the pencil will heat up faster, but unless your doing several mag dumps within a short span of time (which would be dumb anyway) there are no drawbacks whatsoever to the weight savings. Go for a 16" pencil barrel, skip the 14.5, no point. The MOE handguard works great. After your first lightweight build, you will wonder why the HBAR or m4 profiles still even exist on the civilian market.

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I agree with Jackal, the 16" pencil barrel is the way to go for a LW AR. I've done two using BCM and Daniel Defense midlength uppers with MOE handguards that come around 6.5 lbs. No need for a heavier barrel in most applications.

The Midwest Industries SS Gen 2 is the new lightweight king of the hill. I have a Troy/VTAC Alpha rail to compare it to and it is a good deal lighter.

I'm a fan of fluted stainless barrels when I'm looking to save weight. Avoid a full quad rail. It weighs more and tempts you to use the rail space.

A lot of people who I would consider "in the know" like 14.5" guns with pinned muzzle devices. See e.g. the new BCM Jack Carbine. It comes it at 6 lbs 11 oz with a light and front and rear troy irons. That is also with the BCM comp that I would guess weighs a bit more than an A2 birdcage. Add another 3.7 or so ounces for a T1 and mount.

There are disadvantages to a 14.5" with a pinned muzzle device, namely the difficulty of removing the device, which can in some instances affect making other changes as well. For my first AR I got a 16" gun for just that reason. I wasn't of the set up I would settle on and I favored ease of removing the flash hider over the weight and length savings. Like most things there is a trade off. If I was really concerned with weight I would go with the 14.5" barrel.

The weight difference between the 14.5" barrel and a 16" barrel depends on barrel profile. For pencil barrels it is about 2 ounces. However, some people will tell you it is not just the weight it is the location of it. Weight right at the end of the barrel affects handling. Some people feel that a 14.5" gun, more than simply being a bit lighter, balances and handles much better.

If weight is the biggest concern, and an SBR is not an option on the table, I'd vote for a 14.5" barrel with a pinned muzzle device.

A gun with an optic, irons, and a quality light that comes in under 7 lbs is a handy rifle IMHO.

With a light barrel POI will shift slightly more and sooner as it heats up than it would with a thicker barrel. However, unless it is supposed to be a precision rifle POI will not shift enough to really matter. I'm a big fan of light weight barrels for a general use carbine.