One Technology That Could Change the Small Arms Game: OWL Tracers

Yesterday, we discussed the past, present, and future of infantry small arms calibers. That post was a highly introductory one, and there’s much, much more ground to cover on that subject. Today, we’ll talk about a technology that didn’t quite make it into yesterday’s discussion.

That technology is the Army’s non-incendiary limited angle visibility tracer round, called the “One-Way Luminescence” (OWL) tracer. Conventional tracers use consumable pyrotechnic compound inside the base of the bullet to produce a bright flash that marks the trajectory of the projectile in flight, allowing for aiming corrections and dramatically improving hit probability for machine guns over longer ranges. Tracers have been an essential military ammunition type since the early 20th Century, but their incendiary-based technology imposes a number of limitations on the ammunition configuration as a whole. Because they must contain enough pyrotechnic compound to burn throughout their flight, they tend to be longer than their corresponding ball rounds. This additional length can limit the aerodynamic characteristics of both tracer and ball projectiles, if the tracer approaches the maximum possible spin-stabilizable length (about a 7:1 length to diameter ratio, although for military projectiles it is closer to 5.5:1 due to additional considerations). Also, designing incendiary tracer rounds to closely match the trajectory of ball, AP, and other types of ammunition is a serious challenge for engineers, and in practice tracer rounds often given only an approximation of the points of impact for ball ammunition. Finally, incendiary tracer rounds are visible not only to the gunner and his team, but to the enemy being fired upon, as well.


OWL-type non-incendiary tracers can be applied to the bases of standard ball ammunition, and improve the barrel life of the weapons firing them, while also bringing a whole host of other benefits.

OWLs promise to substantially improve this situation. Instead of using incendiary compound, OWL tracers utilize an inert glowing substance applied to the base of a standard ball projectile. The luminescence of this substance is activated during firing, either by the heat, pressure, or other side effect, and in theory provides a trace for the gunner that can be used day or night, in any condition. Not only does this avoid the length problems of conventional tracers, it also creates the possibility for every single round fired to trace, removing the discrepancy in trajectory between tracers and other types of ammunition. This also eliminates one-in-six less terminally effective dedicated tracer bullets from the belt or magazine and replaces them with more effective standard projectiles. When combined with new EPR-type projectiles, OWLs also offer one unified ball/tracer/AP load, greatly improving the consistency and effectiveness of the projectiles being sent downrange while significantly simplifying logistics.


The glowing bases of OWL tracer projectiles.


The most significant benefit of OWL tracers though, is their eponymous quality of being only visible through an approximately 30 degree arc from the base of the bullet. This makes it extremely difficult for the enemy forces being fired upon to see the incoming rounds and avoid them or return fire, which, needless to say, offers a huge advantage for US and allied forces.

Nathaniel F

Nathaniel is a history enthusiast and firearms hobbyist whose primary interest lies in military small arms technological developments beginning with the smokeless powder era. In addition to contributing to The Firearm Blog, he runs 196,800 Revolutions Per Minute, a blog devoted to modern small arms design and theory. He is also the author of the original web serial Heartblood, which is being updated and edited regularly. He can be reached via email at


  • carango772

    one of hte most interesting pieces of reading i have found in a while

    • Mario AK


  • politicsbyothermeans

    Awwww… but then we don’t get to say that tracers work both ways.

    • Major Tom

      You still can. Even OWL’s aren’t invisible. It just means if you see the tracer, he missed.

      • Jwedel1231

        And the guy shooting at you is behind you, meaning you are looking the same way, since they don’t work both ways anymore.

  • I wonder how this will differ from the Cold Tracer developed by Glow Ammo.

    • Mike Lashewitz

      It is brighter.

  • DIR911911 .

    ok , ok . . . I’ll take two boxes

  • Xeno Da Morph

    Way better than Soul Glow tracers.

    • zippiest

      Leave Chicago and Detroit out of this!

      • Bob

        I don’t get the joke, even after a quick Googling…

        • Billy Jack

          I’m guessing a reference to “Coming To America” starring Eddie Murphy and Arsenio Hall. Soul Glow was a fake hair care product (curl activator) similar to real products used for Jheri Curl type hairstyles. It’s an older hairstyle where African Americans would get a perm with curlers and heavily moisturize – so heavily it would drip. A round soaked in curl activator to make it a tracer is hilarious so laugh Bob. Laugh dammit.

  • Well pyrotechnic tracers do have the advantage at times of starting fires though that might be a disadvantage too. So if they achieve trace with this method the original reason to going to the longer bullets and hence the 62 gr ball rounds goes away, does that mean that they will go back to 55 gr?

    • No, the reason to go to 62gr was the better ballistics, not the tracer round.

  • ExMachina1

    Color me skeptical but I do not see this as being a substantial improvement. Even assuming it works as advertised, it only sounds like it will be useful in (very?) low light so target acquisition at range will still be ultimately limiting.

    • micmac80

      The leagest improvement is that traces can actualy fly the same path as rest of the bullets , tradition tracers don’t as the round weight is being depleted when it burns.

      • Sianmink

        Basically if every round is a OWL tracer, it should still be more effective than 1-in-6 standard tracer, especially over longer ranges where they’re actually useful.

    • The program is centered around requirements for all-weather trace.

      • ExMachina1

        “All weather” and “all conditions” are different thing though–all the public info I can find about the OWL suggests the current technology is not ideal and is still limited to low-to-no light conditions.

        • That is why the Army is conducting a technology development program.

  • BrianZ

    Intersting. I would question the visibility (intensity) of the luminescence at extreme ranges or in bright daylight. Obviously current tracers burn extremely bright which is why they are visible over their entire trajectory day or night. I wonder is there would be a need for some optical aid the shooter would need to see where the round went?

    • RISKY

      Imagine OWL tracers in near infrared that can be seen with NVGs but not with the naked eye. Now that’s cool…

  • Bill

    Does this mean I wont have to fight impromptu wildfires with a plastic leaf rake and a half-empty bottle of Mountain Dew?

    • Shocked_and_Amazed✓ᵛᵉʳᶦᶠᶦᵉᵈ


    • Tassiebush

      It’s probably a good thing I don’t have access to tracers. I’d be using a T-shirt and a bottle of moonshine

  • Jeremy David Thomson

    No mention of toxicity or otherwise of the OWL compound(s). Perish the thought that some … opponent … should suffer an allergic reaction to inhumane US poisoned bullets

    • Billy Jack

      Hopefully it’s depleted uranium! Recycling helps us all!
      We just need a depleted uranium mascot like Joey The Uranium Badger.

      I’d hope it wouldn’t pose a threat to troops, officers or range personnel who have to handle them. If anyone knows the name of an actual OWL round maybe we could find a MSDS for it. I personally wonder if we are going to catch a serious uptick in veterans with cancer from the DU munitions used in the various Middle Eastern conflicts. No point in maximizing present day lethality and not thinking about tomorrow.

    • Shocked_and_Amazed✓ᵛᵉʳᶦᶠᶦᵉᵈ

      Oh, heavens. It would be a shame for the person being shot in a war to die </sarc

    • Peadair

      What ever you do, do not shoot at me with a Cashew Coated bullet, I might die from the fumes of the bullet if it misses. 😀

    • Chase Buchanan

      The whole idea is to kill the opponent enemy. However, toxic compounds can harm not only the enemy, but also the US soldiers who have to handle them, and the civilians who might come in contact with the bullets after they’ve been fired at the enemy. Preventing harm to US soldiers and local civilians is the whole point of killing the enemy in the first place, so while we’re at it, we should try not to poison them.

      • Mike Lashewitz

        You mean like DU?

        • displacer

          the US military has literally never issued a DU round which fit into rifle magazines. They were used in very large rounds like anti-tank shells or the GAU/8’s 30mm shells, but those start at the size of your forearm and go up from there. The standard infantry rounds for the US are all ball ammo, which is bimetal FMJ over a lead core, with some possessing steel or tungsten penetrator cores.

          … wait, aren’t you the guy who derailed discussion of Scalia’s death into weird ramblings about how 9/11 was an inside job because you wrongly thought all the tower debris was the exact same size and believe angular momentum is a lie?

  • Billy Jack

    I noticed in a YT video below that the OWLs used in an MP5 were red. Do they also use different colored OWLs based on expected usage? Red for CQB etc since wavelength wise it wouldn’t be as visible at a distance? If so that’s pretty cool.

  • White Knight Leo

    Oh that’s neat. That’s really neat. Future battlefields are going to look like both sides have Star Wars blaster rifles!

    • Shocked_and_Amazed✓ᵛᵉʳᶦᶠᶦᵉᵈ

      Just what I was thinking

    • Rooftop Voter

      With the same sound effects? I hope so. Twing——Twang!

    • Coolhand77

      I wonder if they could be color coded…you know, Green for Imperial troops, Red for Alliance troops? or something like that 😉

      • Blake

        Yeah they most definitely can. In WWII it was really easy for our Marines to know which side tracers were coming from as our tracers were red and the Japanese tracers were green.

    • BDUB

      A night already does look like that. This tech is actually trying to fix the problem by limiting the visibility of the round to a 30 degree rear facing. Easier to walk fire onto target without drawing return fire.

  • Southpaw89

    Was going to question how well they’d show up but that’s not bad, wonder how they’d do at longer ranges though.

  • Budogunner

    In theory these tracers would be suppressor friendly. That is worth it for the giggle factor alone.

    • iksnilol

      Won’t regular tracers work equally well? The tracers I’ve seen ignite after leaving the barrel.

  • wetcorps

    Pew pew pew

  • Shocked_and_Amazed✓ᵛᵉʳᶦᶠᶦᵉᵈ

    Wow. I want some

  • Shocked_and_Amazed✓ᵛᵉʳᶦᶠᶦᵉᵈ

    I want to start long range shooting again. If this is visible at distance, it would be a long distance shooters dream

    • DwnRange

      Why? when with a properly positioned spotting scope one can already “see” the flight-path of the bullet sans any tracer, (or at-least your spotter can, as this has been a method of calling corrections for decades when shooting at long ranges)……..

      • Shocked_and_Amazed✓ᵛᵉʳᶦᶠᶦᵉᵈ

        I don’t have a spotter. I used to have one but he’s been dead over a decade know. I guess I could rig some kind of video camera but these tracers would be cheaper and better.

        • DwnRange

          And unless you have sent tens of thousands of rounds down range it’s highly unlikely you will have trained your shooting eyes to NOT CLOSE when pulling the trigger and lose sight of the OWL round thru the rifle scope. It took me years of long range shooting (600-1000 yds) to be able to see 223 rounds in flight thru the rifle scope and we are talking a lite recoil caliber round here. I still have trouble with eye flinch in medium to high recoil calibers.

          Even IF they develop this tech I suspect it will be of little value to those who shoot long range with “custom” hand-loaded rounds.

          • Shocked_and_Amazed✓ᵛᵉʳᶦᶠᶦᵉᵈ

            Looking for all the help I can get.

          • Shocked_and_Amazed✓ᵛᵉʳᶦᶠᶦᵉᵈ

            Thanks for the advice. I will continue on

  • HAHA73

    I like fire not glow

  • Tassiebush

    OWL tracers will leave the other side asking “Who who is shooting at me?”

  • Raguel A’septem

    So… what would be the difference between these and drilling the base of a bullet, filling with glow paint and capping with clear 2000lb epoxy?
    I’m thinking something like this could be done at home by reloaders without some $1/rnd cost (plus, the ability to make tracers from odd calibers like 6.5mm, .270, .338, .45 & .50)

    • noob

      That looks like what the prototype is (with the hole bored dead concentric which matters a lot at 180,000rpm).

      The final product might use a more exotic compound for better visibility. Or for being visible in nvg only.

  • Marc

    The upper pictures appears to be standard strontium aluminate powder glued to the base of the bullet. Easily reproduced at home.

    • Shocked_and_Amazed✓ᵛᵉʳᶦᶠᶦᵉᵈ


  • Evan

    Seems like a cool idea, if they can get it to work in daylight. I can’t see any real disadvantages.

  • Mike Lashewitz

    Your geekness is showing again Harry…

  • A Fascist Corgi

    So much for your arguments against the 6.5 Grendel replacing the 5.56. All you have left is the weight difference now.

  • displacer

    Find me one single reference to ANY depleted uranium small arms round. If you carried “six magazines” of something it wasn’t depleted uranium, most likely M855 or M80 which is just copper, lead, and in the case of the former steel.

    You won’t even get irradiated by just being near DU, it’s less radioactive than the naturally-occurring uranium found in seawater or the earth’s crust hence the “depleted” part. It’s primarily an alpha emitter, which is blocked by your skin, and you’d have to inhale free-floating particles to be exposed to radiation from DU. It can pose lung cancer risks if you’re on the receiving end or spent a lot of time near sizable DU impact sites caused by vehicle-mounted weapons, but you were not rendered sterile by the ammo in your magazines. I mean jesus christ, even if you WERE carrying mags full of DU (and you weren’t unless the military made super secret 7.62 or 5.56 DU rounds and only gave them to you) DUs alpha particles would have ben stopped by the layer of dead skin we all have and the few beta particles it emitted would be blocked by your clothes or anything else thicker, like bullet jackets or mag bodies

    • Mike Lashewitz

      Damn dude I was there where were you? Smokin pot and jerkin off?

      • displacer

        I guess was paying attention during my college physics, chemistry, and biology classes unlike some other people.

        Have you found the found as much as the model designation of your supposed depleted uranium rifle cartridges which you say gave off so much radiation they made you sterile? It’d be awful easy to make me look like an idiot by just posting a single, solitary reference to this DU ball ammo instead of asking for a comprehensive listing of my whereabouts during the course of your service

        • Mike Lashewitz

          I am sterile because the radiation made my children still born and deformed and the military gave me a vasectomy. While you were smokin dope in college I was serving in these places you have never been.

  • displacer

    It’s cool man, I may be a civvie but I’ve spent most of my career in aerospace where most of my coworkers are ex-mil. I know that most of you dudes have your crap in order better than most, while the few nutbars like him are loud but fortunately rare