The Sub 60oz AR Project

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I am fascinated by the push towards light small arms, especially now with a thriving aftermarket for rifles. An entrepreneurial fellow has started The Sub 60-oz AR Project on Tumblr and thus far has made some significant progress. The goal is to create a less than 3.75 lbs rifle for less than $1000.

The Goal

Over the next few months I’m going to build the lightest possible full sized black rifle for under $1k, and share that process with everyone.

There are a few guidelines:

  1. Under 60oz (with optics? with mag? hopefully both, we’ll see how crazy this gets).
  2. Under $1000 cost.
  3. Obviously it will be functional and relatively safe — no glue instead of roll pins, but aluminum and polymer aren’t failure proof.
  4. Polymer is fair-game.
  5. Some hole drilling may be used, within reason, but we’re not going for a swiss-cheese build [warning: AR abuse in link]
  6. Will not use custom ordered parts (fluted 14.5” pencil barrels for $400, etc.)

To answer a few questions:

  • Hasn’t this been done before?!

It certainly has been tried, and with good efforts, but never with a satisfactory result. All projects miss their goal — at no fault of the skill of the builder — they just use the wrong parts. Off the top of my head, ‘60oz AR Project’ (http://sixtyounces.tumblr.com/) ended up with a 72.55oz rifle. 3lb AR [48oz] (MustyYetisTacticalHQ on YouTube) ended up with a77.38oz rifle. I will succeed where others have failed!

  • How much is 60oz anyway?

Well, 60oz = 3.75lbs = ~1.76kg. The density of water is 1kg/L, so 60oz is roughly 1.75L of water. Put in another way, the density of whiskey is ~0.91kg/L, but at 1.75L it comes in a heavy glass bottle… This rifle will be significantly lighter than a handle of Jack Daniels (and cheaper to take shots with).

  • Why?

There are plenty of reasons, but the most obvious is portability and ease of use. Some people find the platform to be cumbersome, and depending on the rifle load-out they may well be right. The rewarding hobby of shooting and firearms ownership should be accessible, and not just in a ‘muddy girl’ pink, 22lr format. I’m sure some hardcore operators would probably be able to literally juggle several 60oz rifles, and that’s understandable. However, for the less fit or smaller in frame, it may make the difference of being able to maintain good accuracy while standing. Another reason would be to use in a 3-gun, but I can’t guarantee that the muzzle brake I’ll end up choosing will minimize recoil rather than minimize weight. Lastly, It’ll be a fun challenge for me, and probably a blast to shoot.

I’ll add posts as I order new pieces, or as I weigh (literally and figuratively) the possibility of different parts.

tumblr_inline_nipbl1cKrD1t5grgx

So far, the author has located a barrel, receivers, magazine, an aluminum(!) bolt carrier.

Its a fascinating read.



Nathan S.

One of TFB’s resident Jarheads, Nathan now works within the firearms industry. A consecutive Marine rifle and pistol expert, he enjoys local 3-gun, NFA, gunsmithing, MSR’s, & high-speed gear. Nathan has traveled to over 30 countries working with US DoD & foreign MoDs.

Nathan can be reached at Nathan.S@TheFirearmBlog.com

The above post is my opinion and does not reflect the views of any company or organization.


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  • Scott Tuttle

    as an AK shooter I find this trend disturbing 😛 You know he says he’s not going for a swiss cheese build but looking at his blog I’m seeing a lot of holes.

    • iksnilol

      I wonder how light we can build an AK?

      • Scott Tuttle

        should be able to get one under 8 pounds for $350 😛

        • iksnilol

          I know milled receiver AKs are about 3.5 kg empty. Could one make an aluminum receiver on an AK? With titanium trunnion?

          • AldanFerrox

            This is entirely possile, I think. Milling a receiver from high-grade aircraft aluminum is not that complicated.

          • sauerquint

            Would the aluminum rails milled into the receiver hold up? The trunnion part could still be steel to keep the cost down, that would be fine with me.

          • iksnilol

            I doubt it. One would probably need separate rails made out of steel or titanium.

        • noguncontrol

          use plastic instead of steel or aluminum , for both the receiver and the trunion.

    • SubSixtyAR

      Fair criticism! At least I abstained from holes in the receivers though.

      Also for the record: I love AKs but would never want to do a project like this with one of them. Imo they have too much personality to make them anorexic.

      • Scott Tuttle

        my first rifle was an AK then I upgraded to an AR but every time I used it I was afraid to get it dirty or that I’d scratch the paint so I sold it and got another AK. owning a new car makes me nervous too.

  • Joe

    Extar EXP-556?

  • M

    Did he specify a barrel length? Didn’t see one.

    • kevin kelly

      The shortest legal one I’m guessing. I doubt he’d go for a longer barrel bc of weight

  • JSHA22lr

    If money wasn’t an issue he should have used a titanium bcg from Boomfab.

    • Cymond

      Aluminum is lighter than titanium.

      • Reise

        If one mindlessly used an identical configuration/displacement of each. Titanium is about 60% denser than aluminum, but titanium is wildly stronger (being over 100% stronger than even T6 aluminum generally and some alloys being over 600% stronger) .. allowing for reduced or ‘skeletonized’ profiles and therefore weight savings over aluminum.

        Additionally, aluminum can have the exact opposite characteristics for durability in such applications as it suffers from compounding fatigue dynamics, whereas titanium is highly ductile .. absorbing stressors rather than being altered/weakened by them, giving it fantastically superior fatigue limits, actually becoming stronger from heat/cold cycles rather than becoming incrementally weaker from stress.

        For a design based upon considerations of aluminum’s features, it’s an awesome material that’s also pleasant to work with, but to accomplish the same task with any radical reduction of weight one needs a superior material.

        • noguncontrol

          titanium is both more expensive and more expensive to machine. the costs would go through the roof, if you used titanium.

  • J.T.

    “So far, the author has located a barrel, receivers, magazine, an aluminum(!) bolt carrier.”

    Umm…

    He finished the rifle 8 months ago and failed to meet his goal.

    • Sadler

      Not sure what link you’re looking at, but his latest post was in late January on what mag he was intending on using. He also says he’s on track for ~58 oz for the completed rifle.

      • M

        I think he clicked on the sixty ounces tumbler that the author referenced rather than the subsixty tumbler

        • J.T.

          Correct. I thought they were the same link in different places.

  • Martin Grønsdal

    what does this really mean: “Obviously it will be functional and relatively safe — no glue instead of roll pins, but aluminum and polymer aren’t failure proof.”

    • kevin kelly

      Yea that part didn’t make sense to me either.

    • phuzz

      I’m guessing (not sure), that he’s trying to say that if he wasn’t building a rifle with lightness as the only goal, he’d pick more durable components, eg NOT an aluminium bolt carrier.

  • Orion Quach

    Screw budgets! Go with a proof research barrel!!

    • JumpIf NotZero

      I love mine on my reece/spr!

  • Aaron E

    Battle Arms was displaying a 3.5 lb. AR-15 at SHOT Show this year. Only 100 were made and at the Show they had already sold nearly 50.

    • sianmink

      They even cut extra metal from the safety selector. XD

  • Don Ward

    It’s an interesting thought experiment considering the recent trend towards heavier weapons (ahem) with 12-16 pound monstrosities clogging up the ranges, magazines and YouTube channels like a Walmart shopper on a scooter in the Little Debbie aisle.

    • Since many shooters fire off a bench exclusively, and only a few times a year, if that, it would be a non-issue.

      A mass-market 12 pound AR is like an economy car. They sell really well, but not usually to a very discriminating user.

      Different strokes.

  • Mark N.

    Sounds like a fun project, but I have to wonder how sturdy the final project will be. The barrel on my build came in at 2 lbs 13 oz all by itself. I would be perfectly happy with a 5.5 lb rifle, like the M1 Carbine. In fact, what I might really like to have is an M1 Carbine chambered in 300 blk.

    • Raven

      Mini-14?

      • Mark N.

        Mini-14 is .223 and works off of a modified Garand long stroke piston, not the M1 Carbine short stroke. Further, Mini-14s use proprietary mags and are not noted for accuracy. And it is not as cool looking as an M1 Carbine… Although it might be possible to do a barrel swap. The main idea here is that there are abundant bullet choices in 300 blk that are not available in .30 Carbine (plus a little more umph).

  • gunsandrockets

    A flyweight .223 caliber AR has a surprising amount of recoil. Very unlike the usual AR-15 feel. I know this from shooting my old Professional Ordnance Carbon 15 rifle. At the time I bought it, advertised as “the lightest .223 rifle in the world”.

    I don’t think much is gained by reducing full loaded weight of an AR below 7 pounds. Of course with a flyweight AR, an awful lot of gear can get packed on before reaching that 7 pound limit!

  • RICH

    I HAVE A MAGNESIUM ALLOY LOWER THAT WEIGHS 5.3 oz. I WONDER IF THIS WOULD BE A GOOD STARTING POINT FOR THIS BUILD ? I WAS PLANNING TO USE THIS LOWER FOR A PISTOL BUILD….!

  • noguncontrol

    so, this ar would be lighter than both an m1 carbine and a roni’d glock. that would be crazy.

  • dan citizen

    I’ve built some very light ARs (a hair over 4 pounds) and they are what the AR was meant to be. Piggy ARs are no fun.

    • Even just a stock Colt 653 carbine is absurdly light compared to the average AR-15 you see floating around these days. I applaud this guy for trying to go as low as possible, but getting it to the < 5.5lbs envelope is good enough for me.

      (It's making me want to buy a 653 upper for my LE6933, though!)

    • Mark N.

      Aren’t these weights accomplished with pencil barrels that flap around like flags when they get hot?

      • dan citizen

        The 60 oz guy said no pencil barrel. I have gone two routes…

        1) pricey composite barrel with carbon fiber wrap… lightweight, rigid, too expensive. Will not do this again.

        2) Pencil barrel, most of which are just the old A1 profile. Tony Rumore of Tromix did a 3.6# AR with a very narrow pencil barrel that was extremely accurate and did not suffer heat problems.

        I hear a lot about thin barrels and inaccuracy, but I have not found it to always bear out in real life. If I were to do it again I would either use a pencil barrel (my last easily outperformed cheaper heavier barrels, hot or cold) or I would use a tension sleeve.

  • SubSixtyAR

    Hey, thanks for the tip. The endplate I use (V7 systems) is aluminum, but it weighs 0.185oz. Maybe I’ll end up switching out to that Damage industries plate.

  • Paladin

    Apparently the one being used for this build is. Maybe you should have read the article before you commented.

  • MR

    SEI used to make an aluminum bolt carrier, not sure if they still do.

  • JR

    My nephew just got back from Afghanistan and just had to buy his first AR. Being on a limited budget he purchased a Core bare bones AR 15. Truthfully I wasn’t initially impressed. My opinion when I tried the rifle did a complete 180. Light, accurate, and ran like a precision machine. Half the weight of my Sig 556 and performed just as well.
    The Core 15 may not be the lightest production 15 available but it certainly changed my opinion on weight.

  • SubSixtyAR

    Hey, great link with good resources for some low weight parts. He and I often choose the same parts.

    However, that thread title is very misleading — OP uses a 22lr polymer upper for the weigh-in to cheat/beat his buddy then switches to a heavier aluminum upper. This is the case for many of the parts he uses ‘temporarily’ before switching to final parts. He also spent over $1,500.