Published on June 16th, 2016 | by Destinee (FateofDestinee)

Lightweight AR-15 Rifle Builds

When I started putting together my first AR-15, my goal was to keep it fairly light weight so that it would be easily maneuverable for me (despite not being blessed with an abundance of upper body strength). In my research, I found several different approaches to custom rifle builds in the interest of weight saving. Most “lightweight AR-15 builds” included shorter and thinner barrels (for example, 14.5″ pencil profile barres with 1.5″ compensators/flash hiders welded to the end), and minimal accessories. Beyond these common weight saving measures, there are other additional approaches to minimizing overall rifle weight: choosing a lightweight AR-15 lower. Here are three examples of lightweight builds with different types of lowers, and the resulting overall rifle weight.

Using Polymer AR-15 Lowers

Jon from the YouTube channel chaos311clarity has a lightweight AR-15 build he calls his “Chaos Carbine,” that measures in at 6.2lbs (unloaded), and one of the chief components of this light AR is his Plum Crazy polymer lower. It also features a DPMS upper (sans brass deflector and forward assist, in the interest of saving weight), a Daniel Defense pencil profile barrel (with Ares Armor Effin-A compensator), and a Giessele Super Dynamic 3 gun trigger.

Using Carbon Fiber AR-15 Lowers

Recently, I received a rifle from Windham Weaponry for test and eval (T&E) that features upper and lower receivers of a molded fiber composite (that includes 40% carbon fiber).To see my first impressions of it, check out the embedded video above. Unloaded, this flattop rifle weighs only 6.0lbs (including sights). Because this is a T&E gun, all the parts on it are stock, with the exception of the Troy fixed Tritium iron sights (borrowed from my AR build detailed below). The stock rifle comes with a polymer double heat shield handguard, a 16″ M4 profile barrel tipped with a standard A2 flash suppressor, a stock single stage trigger, an A2 style polymer grip, and polymer six position telescoping buttstock.

Using Aluminum AR-15 Lowers

When I started putting together my custom AR-15, “Bruce,” I was also interested in weight saving, but preferred an aluminum lower. My lightweight AR-15 rifle features an aluminum billet LMT Defender 2000 lower, and weighs in at a somewhat heftier 6.6lbs (unloaded). In the linked video, my rifle features a Daniel Defense DDM4V7 upper with 16″ pencil profile barrel (with a 1.9″ Daniel Defense flash suppressor) a Magpul ACS-L buttstock, Troy Tritium round aperture fixed iron sights, a V-Tac Upgraded Wide Padded Sling, and the stock LMT Defender ergo grip and stock 2 stage trigger.

What parts would you like for your lightweight AR-15 builds?

About the Author

In addition to writing for The Arms Guide and her personal blog, Destinee is also a vlogger. She publishes videos on weapons, gear, and fitness on her YouTube channel every Tuesday and Thursday.


  • NateGranzow

    I don’t think I could have gone heavier with my AR without adding a bull barrel. I just call it “character building” when I’m lugging it around the woods.

    • The lighter, the better. Less weight to hump around.
      But are the priceslower on the polymer parts or are they still trying to rob us?

      • FSDFirearms

        ristin59 We use FMK AR-1 polymer lowers and love them. Our price has never gone above $99.

      • FSDFirearms

        ristin59We use FMK AR-1 polymer lowers in all of our custom AR builds and our price has never gone above $99 – even during the “craze” at the beginning of the year.

        In fact, on my husband’s 6.8, loaded and including a scope, the scale registers 6.7lbs! Can’t go wrong with a GOOD polymer lower!
        FMK offers a lifetime guarantee on their lowers and they’re made here in the US, so you really can’t go wrong with em!

        • That’s cool! I need it lighter.
          Too many years throwing around electrical motors & compressors have done a number on the body.

      • ristin59 For my wimpy chicken arms, it means I can keep the rifle at the high ready for longer stretches of time.

        • I completely understand that!

        • JunkfoodZombie

          You know MAC. Might wanna check into a Tavor. More weight in the rear and a short overall length…..means it handles better and feels lighter. Goes great with any Batman apparel you own as well! 🙂

    • NateGranzow Lol @ “character building.” I have an article coming up about heavier builds… Looking forward to the response on that one. heheh

  • peter3101

    I moved to NJ, here apparently you need to complete 14 forms have 3 signed affidavits, a note from the State Police, and a blessing from the pontiff just to build a lego gun……..

    • NateGranzow

      peter3101 My sincere condolences, Peter.

      • peter3101

        NateGranzow peter3101  Thanks it does not help that my Mother in Law is also in this State. Even great pizza, bagels,  and diners cant make up for that……

        • NateGranzow

          peter3101 Bahahaha. 🙂

    • peter3101 </3 Seriously… I could not live there. Or California, for that matter.

      • NateGranzow

        FateofDestinee peter3101 Or Illinois, Indiana, the entire East Coast north of the Mason Dixon line…

      • peter3101

        Do you know my Mother in law?

    • JunkfoodZombie

      Plus, you have to deal with all those damn jughandles. They suck! XD

  • AlessioBaldi

    Like Boris “the blade” said: “Heavy is good. Heavy is reliable. If it doesn’t work, you can allways hit them with it”. XDI usually go hunting with pretty heavy scoped rifles (my 700 for example weights about 13lb) and shotguns, so ARs and AK for me are just lightweight. But my sisters have some problem handling my AR and AK, both with only iron sights and without accessories, for long periods of time. A lighter rifle can help for sure, but i wander if the pound, or little more, of lessern weight really makes a difference, considering the incrased price and compromises like the thinner barrel.

    • NateGranzow

      AlessioBaldi Love the reference from “Snatch”—great movie.

      • NateGranzow AlessioBaldi That is one of my all-time favorites!
        “What’s wrong with this one?”
        “Nothing. This one’s *tip TOP,* I’m just not sure about the COLOUR.”

        • AlessioBaldi

          I would have bet on that, we seems to have the same all time favorites xD
          From that movies i really enjoy Brickhead’s liners, vut this is also freakung motivating: ” the fact that you’ve got “Replica” written on the side of your guns. And the fact that I’ve got “Desert Eagle .50″ written on the side of mine, should precipitate your balls into shrinking, along with your presence. Now fuck off!” Lol

    • AlessioBaldi I have a heavier/precision build in the works… but it has been slow going with the recent scare. I’ll have some video/article on it in the future, though. ;D

      • AlessioBaldi

        Is that going to be a 20 or a 24″?As a lightweight option, i’d like to have a very lightweight 7.5″. I can’t assemble it on my own, but there are a few gun makers here that build excellent AR on the customer specifics. The price, needless to say, is a little prohibitive.

    • Shoot to hit

      Heavy is reliable, case in point, my M1A with Nat. Match barrel, and 20 round magazine. Light is good, but I like the sturdiness of my M1A more than the light weight compactness of an AR platform. I’m still young though, and the heavy rifle doesn’t seem to tire me out like the rest of my friends and family. For now….

      • AlessioBaldi

        Different rifles for different jobs.
        When i need accuracy, i know weight is my friend. When i need mobility and speed, i know compactness lightweight is my friend.
        But sometimes i bent to a compromise, and end up bearing a 13lb long range rifles up the mountains and into the woods all day long, just for the sake to be sure to hit a deer at any distance lol.
        Great rifle the M1A, allways wanted to own one, as for the Garand.

        • Shoot to hit

          AlessioBaldi Agreed, different rifles for different jobs. My M1A is too big for close up quick shooting in a brushy area, but is a superior rifle for mid to long range shots.  I too like the Garand, it’s one of my favorite rifles,  but I chose the M1A for the detachable magazines when I had to make a choice as to which one to take home from the gun store. Eventually I would like to ad an AR-15 to my gun collection so that I can have a light weight rifle.

      • AlessioBaldi

        Different rifles for different jobs.
        When i need accuracy, i know weight is my friend. When i need mobility and speed, i know compactness lightweight is my friend.
        But sometimes i bent to a compromise, and end up bearing a 13lb long range rifles up the mountains and into the woods all day long, just for the sake to be sure to hit a deer at any distance lol.
        Great rifle the M1A, allways wanted to own one, as for the Garand.

  • Eric R Shelton

    I used an old Cavalry Arms lower- polymer and it has the stock and buffer tube integrated into the same piece. DPMS Lo-Pro upper (open ejection port, no fwd assist), pencil barrel, and even MagPul MBUS sights. My goal for the build was under $600 and six pounds. I came in at 5.2 lbs, but closer to $700 because I didn’t shop quite carefully enough and splurged on a hard chrome BCG for some bling in the Lo-Pro. It’s not as nice as my VLTOR build, but I’d put it up against any Bushmaster/Stag, etc.

  • stevohughes

    I just finished a 70-ounce build. Here is my new project: http://sixtyounces.tumblr.com/

  • nigray

    new frontier polymer lower
    palmetto armory lower parts kit
    phase 5 extended bolt catch
    american gold drop in trigger assembly
    ace skeletonized buttstock
    jp captured spring buffer
    hoague rubber grip
    american spirit side cocking upper receiver
    american spirit bolt
    daniel defense pencil contour cold hammer forged .625 gas block barrel
    tactical enterprises barrel nut
    adams arms .625 gas piston system with adams arms bolt carrier
    samson ev7 ex forearm
    battlecomp 1 compensator
    aimpoint micro t1 2 moa red dot optic
    alamo 4 square aimpoint optic mount
    bronell 20 rd aluminum mag

  • nigray

    new frontier polymer lower
    palmetto armory lower parts kit
    phase 5 extended bolt catch
    american gold drop in trigger assembly
    ace skeletonized buttstock
    jp captured spring buffer
    hogue rubber grip
    american spirit side cocking upper receiver
    american spirit bolt
    daniel defense pencil contour cold hammer forged .625 gas block barrel
    tactical enterprises barrel nut
    adams arms .625 gas piston system with adams arms bolt carrier
    samson ev7 ex forearm
    battlecomp 1 compensator
    aimpoint micro t1 2 moa red dot optical
    alamo 4 square aimpoint optic mount
    brownell 20 rd aluminum mag
    all for about 6.8 pounds. nice frankenrifle built from scratch

  • drmorris9

    I would love if they would sell the Windham Weaponry receiver set stripped.  Put that with a BCM light weight 14.5 carbine barrel with a pinned flash hider and standard magpul MOE furniture and you should be sub-6lb with a high quality and durable rifle.

  • Joseph Goins

    BCM Recce with 14.5″ enhanced lightweight (fluted) barrel and 10″ KMR rail
    Magpul Back Up Sights (front and rear)
    Trijicon MRO
    Larue mount for Trijicon MRO
    Magpul Vertical Grip
    Inforce Weapon Mounted Light
    ————————————
    6lbs6oz

    • Rick D

      how do you like the larue mount for the MRO ?

      • Joseph Goins

        It’s a quality mount. I have the cantilevered version (LT849) because it works better with my night vision. The only “problem” I have with it is an impact shift of approximately 1.2″ at 200yards (~.6 MOA) when I use the quick detach feature, but that is to be expected in my opinion.

        • Rick D

          Mine is going on my SBR so I might stick with the factory lower 1.3 mount for mine. We will see how it feels and runs

  • Rick D

    Polymer lowers have had issues in the past, can’t beat the tried and tested aluminum, I have to disagree with the author. I mean side by side with my AK or anything else the AR is generally going to be lighter by a long shot

    • Joseph Goins

      True. The rifles mentioned here are lighter than most stock rifles, but they aren’t near as light as they can get. Check out this 3lb10oz AR with iron sights: http://www.calguns.net/calgunforum/showthread.php?t=1005966

      I think we ought to have a lightweight build-off.

      • Rick D

        That might be an excellent idea. Very soon Mr Don Adams and I will be having an SBR vs Bull pup battle followed by a FAL vs G3 (PTR 91) battle

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