Making an Ultra Lightweight AR15 Build

The original AR15 was designed to be a lightweight civilian rifle with recoil that would be more forgiving than past, more traditional bolt action rifles. Fast forwarding to today - in the year 2023, what parts do we have available to really hone in on emphasizing weight reduction? Today we explore that with a build list of accessories and parts that focus on producing the lightest possible weighing AR15 today.

2A Armament Balios-Lite Upper Receiver

Photo Credit: Wing Tactical

Sitting at 5.93 ounces is one of the best lightweight AR15 upper receivers from the Balios-Lite family at 2A Armament (now acquired by Nemo Arms). The Balios-Lite AR-15 upper receiver is one of the most lightweight lowers on the market. Like the Aero Slickster, the Balios-Lite ditches the excess weight that is the forward assist as Eugene Stoner would’ve wanted. Recesses are sported beneath the lightning-cut top rail and on top of the charging handle’s window to save weight.

• $241.30
• Weight is 5.93 oz
• Lightning-cut top rail
• No forward assist
• 7075 T-6 milled
• M4 feeding ramp

Faxon Streamline Carbon Fiber 15" M-LOK Handguard

Photo Credit: Faxon 

Carbon fiber is exceptionally strong in one direction with greater tensile strength than steel wire equivalents. It is by no means indestructible as forces acting on it from different directions such as crushing and twisting can cause catastrophic failure. However, its extraordinary resistance to heat absorption and featherlight weight gives it great potential as a lightweight AR15 handguard that's also free-floating.

In partnership with Lancer Systems, Faxon offers the 15” Streamline Carbon Fiber M-LOK AR-15 handguard weighing in at an impressive 6.71 ounces with the steel barrel nut included. Keep in mind though, while you may get the lightest AR15 handguard with carbon fiber options - you definitely do not want to drop your rifle as the handguard could crack on impact.

• $321.08
• 6.71 oz
• 15” M LOK

Lower Receiver

Photo Credit: 5D Tactical

An AR15 lower receiver is not a pressure-loading component and can be built entirely without heavy steel components. Receivers that get the job done can be made via cast, forged, billet, or polymer. As long as the receiver has good tolerance, it is difficult to end up picking one that’ll fail you in regular use.

The weakest failure point of the AR upper receiver is within the buffer tube ring. It takes on the strain of the bolt carrier group moving against the buffer kit and is consistently the first part to break typically with polymer AR15 lowers which is one of several reasons we do not recommend polymer lower receivers. 

For peace of mind, we'd still go with the lightest possible aluminum lower that we can find. Every now and then we offer forged 80% lowers. Those would be our favorite go-to option for the receiver's material strength and lightweight.

Magpul MOE AR Grip

Photo Credit: 5D Tactical

An AR grip is largely a personal preference and is one of the easiest components to swap. If you opt for any standard mil-spec AR lower, our personal choice would be the Magpul MOE AR Grip.

• $19.95
• 2.8 oz

Stock

Photo Credit: Mission First Tactical

Short of a bare buffer tube, the BATTLELINK Minimalist Milspec Stock is certainly one of the lightest AR15 stocks around. Its design is simple, it's lightweight, and a very shoulder-able device. It adds only 5.8 ounces to the build. Pretty decent savings since most stocks weigh in anywhere from 8 to 13+ ounces.

• $59.99
• 5.8 oz

Proof Research Carbon Fiber Barrel

Photo Credit: Proof Research

Proof Research’s line of carbon fiber barrels is some of the highest quality and lightest AR15 barrels around. Life for these barrels starts as standard steel 416R blanks. Sections of the barrel’s outer diameter are milled to remove material to be replaced with carbon fiber.

It uses just enough of the steel barrel blank to be structurally sound when supported by walls of carbon fiber resin. While the composite barrel’s longevity may not match that of cold hammer-forged barrels, the Proof Research AR-15 Carbon Fiber 223 Wylde Barrel is the lightest option available.

If you want the ultimate weight savings option, be prepared to pay a pretty penny for this lightweight AR15 barrel. This is a company and brand that hunters and long-range precision rifle competitors alike will often choose their barrels from (that says a lot).

• $999
• 9 oz
• 14.5" barrel length
• 1:7 twist
• Mid-length gas system
• .750 gas block
• 1/2-28 thread

Triggertech Diamond Flat Drop-In Trigger

Photo Crediti: Triggertech

Triggertech triggers are among our top favorite brands to use when it comes to drop-in triggers. They're small, compact and provide a ton of performance. If you're looking to really dial in your trigger, look no further than the Triggertech Diamond option as it can be adjusted to have a 1.5 to 4.0 lbs of pull weight. We prefer the flat profile but if you like curved triggers more they have that option too. 

• $304.99

Radian Raptor-LT

Photo Credit: Radian Weapons

This ambidextrous charging handle from Radian Weapons is made out of high strength fiberglass reinforced polymer which features an 8% reduction in weight when compared to its aluminum version. All we personally use are Raptor- LT's so we are definitely slightly biased.

• $74.95
• 1.20 oz

Radian Talon Ambidextrous Safety

Photo Credit: Radian Weapons

When it comes to safety levers, the weight is really negligible. We think what makes a good safety lever is how easy they are to manipulate and how they feel in terms of ergonomics. 

The Talons are made out of billet aluminum and use a spring-loaded retention stud which makes them very easy to install as well. If you like that mil-spec feel, you can set these to have a 90 degree turn, otherwise rotate the shaft and install these at the 45 degree angle setting. 

• $59.65
• 0.53 oz

JP ULMOS Bolt Carrier Group with JP Enhanced Bolt

Durability be damned, we want less weight and JP Enterprises delivers with the aluminum version of their JP Low Mass Operating System. The JP Ultra LMOS Bolt Carrier is best paired with a titanium bolt and firing pin to prevent slamfires. Note the lack of serrations intended for a forward assist.

• $485.00
• 5.8 oz

Buffer

For a mid-length direct impingement gas system, an H2 buffer will suffice. Make sure that the buffer is of carbine length if you’ve opted for the KE Arms KP-15 lower receiver. For this build, we went for the Kaw Valley Precision AR-15 Heavy Tungsten Carbine Buffer to go with the mid-length gas barrel.

• $29.95
• 4.3 oz

Titanium AR-15/M4 Takedown Pin Set

Using the same principles of the V Seven ambidextrous safety, the Titanium AR-15/M4 Takedown Pin Set is machined from grade 5 titanium rather than steel to reduce 45% of the standard mil-spec takedown pin weight.

• $24.95
• 0.26 oz

SLR Rifleworks Sentry 7 Gas Block

Photo Credit: SLR Rifleworks

Sentry 7 Set Screw Adjustable Gas Block is the .750 diameter of their gas blocks that deliver a reputation of easy installation and quality performance.

• $134.18
• 0.6 oz
• 0.750

C-More Sight 

Photo Credit: C-More

For lightweight and quick sight acquisition the polymer-housed C-More red dot reigns supreme. While lacking in durability compared to Eotechs and Aimpoints, the housing is particularly low profile and thin to the benefit of its field of view. The C-More Railway Red Dot Sight adds 5 ounces to our build, twice as light as most of Eotech’s popular holographic sights.

For comparison:

1. EXPS is 11.5oz (325 g)
2. XPS is 9.0 oz (255 g)
3. 512/552 is 11.2 oz (317 g)
4. 518/558 is 13.8 oz (391 g)

• $279.00 for a standard switch
• $289.00 for click switch
• 5 oz
• Easy sight acquisition because of unobstructed housing
• Not as durable as most red dots

Trijicon MRO

Photo Credit: 5D Tactical

We are big fans of the Trijicon MRO and have created a convenient bundle with the option for a Lower 1/3 or Full Cowitness mount. Typically, these expensive optics don't come with mount and have to be purchased separately. The MRO has a large aperture and field of view which make target acquisition fast and easy. We also include a Trijicon Kill flash in this bundle to reduce lens glare and provide 

• $573.99
• 3 oz 
• $137.00 (LRP Mount)
• 0.25 oz (LRP Mount)

Let’s Get You Armed

Although you certainly don't have to follow this guide to a "T", it can serve as a good comparison for if you want to find other comparable options. Perhaps you'll find other parts more to your liking whether they are more affordable or even lighter than what we've found. 

If you'd like to have an even more hands-on approach we can guarantee that our 80 lowers and jigs will give you the most personal touch to building an AR15. If you fancy a new build starting with an 80 percent lower receiver, check out our selection today!