We set out to build the lightest AR possible and when it was all said and done, it weighed in at 4.5 pounds. Here’s how we did it…

Two years ago, it would not have been possible to build a functioning AR-15 that weighed under 5-pounds with off-the-shelf parts. They were just not available. Thanks to companies like Battle Arms, V7 Weapon Systems and 2A Arms, that has all changed in the last few months.

We set out on a mission to build the lightest AR possible and when it was all said and done, it weighed in right at 4.5 pounds. In this article we’ll share how we accomplished the build and discuss how well it shoots.


There are essentially two metal options when it comes to lightweight receiver sets on the market with more and more coming every day. Take note we said metal, as we are not factoring in composite polymer based lowers.

  1. Battle Arms Development – The BAD556-LW is not only badass looking, it is light: weighing in at 6.84 ounces for the lower and 6.31 ounces for the upper for a combined weight of 13.15 ounces. The BAD556-LW is made from tough 7075-T6 Aircraft Aluminum and precision CNC’d to very tight tolerances. MSRP is $499.
  2. 2A Arms – The Balios Lite is equally as sexy and is mildly lighter than the BAD556-LW. The Balios Lite comes in at 6.5 ounces for the lower and 5.85 ounces for the upper, totaling 12.35 ounces. The Balios Lite is also made from 7075 and retails for $519.99

Either of these options makes a great foundation for your ultra-light build and it really comes down to which looks best to you. We will say that in our experience, Battle Arms puts a lot of attention to detail in their machining and their customer service is top-notch. We have heard great things about 2A Arms but we have no experience working first-hand with them.


For this article, we choose the 2A Arms Balios-Lite because we were going for the absolute lightest possible build. In order to achieve that, we had to use titanium parts for the majority of the components and enlist a specialist in that industry, none other than V7 Weapon Systems out of Grants Pass, Oregon.

V7 makes just about everything for the AR out of titanium, which is stronger and lighter than aluminum, but very expensive and time consuming to machine.

In the case of this build, V7 titanium was used for the Bravo Company patterned KMR barrel nut, Safety, Muzzle Brake, Magazine Release Bar and Button, Bolt Catch, Buffer Tube, Castle Nut, Buffer Retainer, Buffer Spring and a few other small parts. Basically, all of the small components with the exception of the takedown pins from Battle Arms Titanium EPS-TI pin set were made out of V7 titanium.

For the trigger we used the Elftman 3-gun match trigger, which utilized a skeletonized trigger and hammer. For the trigger pins, we used the partially hollowed out CMC Trigger pins.

The polymer ejection port door is from Strike Industries, the grip used is from Umbrella Corporation, the stock is from Battle Arms, and the sights are from Bobro Engineering.

The heavy hitter parts and the ones that usually make up the most weight are the rail, bolt carrier group (BCG), and barrel. We spent a lot of time researching the lightest options available on the market. We chose the ultra-light Keymod magnesium alloy KMR rail from Bravo Company Manufacturing (BCM), the titanium BCG from Boomfab and the barrel from Voodoo Innovations.


Altogether, she is light, but how does she shoot?

The first thing we hear from experienced shooters is that an AR this light must be very hard to control, especially on follow-up shots. Well we are here to tell you, that is true and…false.

A properly tuned gas system with the right muzzle device makes for a very soft shooting AR. Less Mass = Less Recoil. This gun is far gentler than many of my ARs and it is fast shooting too.

In fact, we had the opportunity to shoot the Battle Arms Sub 4lb OIP rifle at Shot Show this year. The recoil was so light, we barely felt it. More info about that one here

We attribute several factors for recoil: weight, balance, muzzle device, and gas flow to result in a proper tuning. It is up to you to figure that out, this was just our recipe and it worked well.

* The views and opinions expressed on this web site are solely those of the original authors and contributors. These views and opinions do not necessarily represent those of Guns & Tactics Magazine,
the administrative staff, and/or any/all contributors to this site.


  1. You are trying to build the lightest AR-15 possible, and you put a 15″ handguard and leave the dust cover on… If you had bought the 7″ rail and gone with a carbine gas system you would have saved weight on the gas system, you would have saved 4oz on the handguard since the 7″ weighs 7oz and the 15′” weighs 11oz, and you could have saved the better part of an oz getting a dust-cover free upper. I bet that rifle could be made to weigh less than 4lb.

  2. My AR15 in 6.8 SPC II with 16.1 inch barrel weighs 48.12 ounces with no scope. My AR 15 with Faxon 16 inch pencil 556 barrel weighs 47.06 ounces.

    My AR 308 weighs 4.48 pounds without scope, try topping that!!!!!!

    Because there is no muzzle brake my 6.8 kicks slightly harder than my 4.48 pound R 308

  3. I built my Lightweight AR with cost and weight in mind, I just shopped online and compared weights of parts, mine tips the scale at 38.95 oz. pencil barrel, reduced mass BCG, Magnesium lower, standard upper minus dust cover of forward assist, a few titanium parts, carbon fiber handguard from ebay. She shoots great and feels like a feather compared to my other ARs!

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.