Custom Aluminum Turbine Shotgun Slugs Fired for the First Time

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Aluminum turbine slugs out of a shotgun are a pretty interesting concept. This custom-made turbine slug is quite a work of art, too.

These custom-made slugs were made on a CNC machine specifically to be launched from a shotgun. The rifling cut into the slug itself is meant to help stabilize it in flight to the target.

A variety of projectiles can be shot out of a shotgun. This all-aluminum projectile just might become another selection in the future.


  1. avatar Manse Jolly says:

    Keyhole..hmm. Not sure thats how it’s supposed to work but ok.

    1. avatar Norincojay says:

      Looks like a failure because of the keyholing. They should keep trying though!

  2. avatar Tec's Dad says:

    FYI I enjoy these experiments. Fiocchi is pronounced Fee-oh-key, grazie!

  3. avatar Cliff H says:

    Mu question is – If the slug fits INSIDE the plastic shotgun shell then how tight does it fit in the bore? Seems like a lot of slop and wobble going down to the muzzle which would interfere with its getting up the required spin and induce that tumbling .

    1. avatar Geoff PR says:

      Yup. It needs a sabot…

      1. avatar Tec's Dad says:

        It would need a sabot if it was shot in a rifled bbl; it was shot in a smoothbore. A sabot(shoe) only makes a difference when the bore is rifled… these projectiles were given a rifling profile that did not works as designed…

        1. avatar ACP_arms says:

          Actually a sabot can be used if barrel is rifled or not. The M1A2 Abrams main gun, the M256A1 is a smooth bore and can shoot the M829, a sabot round.

        2. avatar Geoff PR says:

          “It would need a sabot if it was shot in a rifled bbl; it was shot in a smoothbore.”

          First off, what ACP said.

          The sabot will keep the slug centered in the bore when it exits the barrel and the sabot ‘shoe’ peels away from the projectile.

          It’s tough to see in that video, but it’s quite possible the projectile exited the barrel cock-eyed and never had a chance to recover.

          Someone ought to mention to Taofledermaus an improvement in the turbine ‘vanes’ would be have the machinist ‘sharpen’ the front edge of the ‘vanes’ so they can ‘bite’ into the airstream easier when exiting the barrel. That just may ‘start’ the rotation of the projectile enough to keep it stabilized in flight.

          The machinist may want to pay more attention to the projectile’s ‘center of gravity’ in flight by tapering the projectile smaller in front and larger in the rear to enhance its stability ‘in flight’.

          The machinist needs to Google “center of gravity in flight” to see what I mean on that…

      2. avatar BLoving says:

        Can’t recall the source, but some experimentation has been done shooting sabots through unrifled shotgun barrels and the short answer is it’s a waste of time beyond 25 yards – that bullet is gonna tumble.
        Despite this, I pick up a box of sabots for my shotty whenever I find them on clearance. Why? Because I’ll only use them at 25 yards or less in very thick cover.

        1. avatar Geoff PR says:

          “…and the short answer is it’s a waste of time beyond 25 yards – that bullet is gonna tumble.”

          Eh, not always.

          I’ve seen videos of slugs with stubby fins on the rear of the projectile that do a remarkable job of keeping it flying true and stable in flight.

          There’s a video out there of a B-52 that lost its vertical stabilizer and they managed to land it one piece.

          There was a *tiny* stub of the V-stab remaining after they lost it that was *just* enough to allow them to land it:

    2. avatar Big Bill says:

      Cliff, the chamber of the shotgun barrel is larger than the rest of it, to allow room for the shell casing and still keep the slug in contact with the barrel tube. Little to no slop involved.

      A sabot would work if the slug were smaller in diameter than the bbl, no matter what the shape of the slug, but only to make the diameter of the saboted slug the same as the bbl. If the bbl is rifled, then the slug will spin. Otherwise, it won’t.

      Trying to compare a slug out of a shotgun bbl to a multi-engined airplane is futile. The plane can be controlled with the engines id the vertical stabilizer is gone; it’s been done, but it takes some fine piloting. No such control is possible with a slug.

      It’s been my observation that a slug fired from a smoothbore bbl needs careful design to keep it stable; since spin is very hard to impart by airflow (supersonic aerodynamics don’t really allow that easily with “turbine” designs, and fins are too short to project into the airstream outside of the shock wave to provide stabilization and still fit in the bbl. The right design is what we already have: a nose-heavy design works well in a supersonic slug. If the bbl is rifled, then other designs work well, but they can’t be made of a hard metal, such as aluminum. Even a rifled choke can work, but a hard metal will damage the choke itself. SO, lead or something similar will work.

      As an aside, the rifling on a lead commercial slug isn’t there to provide spin; it’s to allow the slug to swage down if it’s shot from a bbl with a choke. I know most of us understand that, but not everyone does.

      Personally, I enjoy Tao’s work in showing us these designed slugs. They usually demonstrate that these designs, such as this “turbine” design we see today, don’t work, because the supersonic aerodynamics don’t allow the “fins” to bite into the airflow to provide the spin needed for stabilization. A few work, but the design needs to allow either a nose-heavy weight distribution, or a design that allows the fins to both fit the bbl to allow a straight exit from the bbl and still bite into the supersonic airstream, not an easy task.

      Just like making clicking on “Notify me of follow-up comments by email” work evidently isn’t an easy task.

  4. avatar Steve says:

    In order to shoot more than just one at a time by stuffing the thing into the chamber, the slug has to be actually loaded down into the hull. This whole thing is just stupid since we already have many choices in slugs that actually work that you can fill a shotguns magazine with. Just because you can do something, doesn’t mean you should do it.

    1. avatar Swarf says:

      So… not familiar with Taofledermaus, then?

      A third of the propellant force is blowing past the projectile because the vanes are open the whole length.

      All that turbulence just ahead of the slug the whole time can’t be doing good things for stabilization.

  5. avatar Dyspeptic Gunsmith says:

    I fail to appreciate what the point of these experiments is.

    Is it to just shoot stuff and watch pieces go flying? OK then, go to it and have fun.

    Is it to make a better slug? Because it would take a really big leap forward to make me (or anyone else who knows a few things about shotguns) give up on Brenneke.

    1. avatar Geoff PR says:

      “Is it to just shoot stuff and watch pieces go flying? OK then, go to it and have fun.”

      It’s part of that channel’s shtick for their fans to send him weird things for him to load and shoot and to video them in slow-mo in flight…

  6. avatar strych9 says:

    Am I the only one who thinks this is a complete waste of time and money?

    Like Steve said, just because you can doesn’t mean you should.

    1. avatar Geoff PR says:

      “Am I the only one who thinks this is a complete waste of time and money?”

      Uh, I think he gets paid from the video views.

      Well, a waste of *your* time, that he gets paid for…

      1. avatar strych9 says:

        Based on the way they operate I suspect it was sponsored on Patreon but I don’t actually know.

        Other than for “entertainment purposes” on the internet this seems like one of the dumber things I’ve ever seen. Especially if you blasted someone with one of those things. An anti-gun DA would have a field day going after you for shooting someone with one of those things.

        1. avatar Manse Jolly says:

          Imagine the wound channel if that thing pinholes into a torso.

          Pictures in a courtroom.

    2. avatar Badwolf says:

      I’m thankful there are people who “waste” time and money on experiements like this and shares the results. Saves me the trouble and I learn something new.

  7. avatar Bob Watson says:

    Nine out of ten four-year olds agree. You are supposed to do it the right way.

  8. avatar DaveL says:

    What do I want in a projectile? I want something that’s dense, so it can hold on to its kinetic energy for longer and hit harder. I want something that’s stable in flight and shoots straight. I want something that’s simple and inexpensive to manufacture.

    But hey, zero out of three ain’t bad.

  9. avatar Tommygun851 says:

    I’m not seeing how they load it in the shell !? If there is a wad to check the expanding gases, then the slug is not turning in the barrel. When it exits the air imparts a spin in the direction of the rifling on the slug. If any of the gases blows by the slug in the barrel, it will impart a spin in the opposite direction. When it hits the air, it will want to spin the other way actually stopping it from spinning causing it to de-stabilize! Without knowing how it’s loaded, it is tough to analyze the problem. Also aluminum is way too hard a material to shoot threw a steel barrel without some type of patch around the slug, be it plastic, paper or soft metal to buffer it as it goes down.

  10. avatar Roymond says:

    This is what’s called a “trial of concept”. Unfortunately, they didn’t have the cameras running in any way to allow them to tell if the slugs were spinning at all; they were only judging by how stably they flew, which as a secondary measurement isn’t that useful. I’d like to see them do it with the cameras downrange not far off the flight path so they can measure the spin, if any. If there is spin then the concept is basically established, and they can play with turn rates, vane thickness, valley shape, etc. It wouldn’t be the first time a new concept looked horrid on first try but eventually led to something valuable.

  11. avatar Bob Townley says:

    Hey people, if someone didn’t “experiment” we would still be throwing sticks and stones, there is nothing that cannot be improved with experimentation, right? Besides it give us all something to watch and comment on besides Covid-19–right?? Just enjoy these things, that is what they are meant for anyway.

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