NYC CNC Folding Fin 12 Ga “Missile”

My friend John Saunders, of CNC NYC, teamed up with Taofledermaus to make CNC aluminum projectiles. It was Taofledermaus’ idea to have a projectile that would have pop out fins.

John made three different slugs. Each successive one more intricate than the previous.


Here is the first slug. Pretty basic. It is a pointed projectile.

Slug 2


The second is an evolution of the first. He cut spirals along the side and machined the base away. Taofledermaus said this shifts the weight toward to front possibly making it more aerodynamic.

Slug 1


He also cut the tip down in preparation for the third version.

slug 1 front


This is the final result. A hole is drilled down the center to allow air to pop out the fins.

Slug 3


The idea is sound. Taser made a successful fin stabilizing taser robot that shoots out of a 12ga shotgun.



Here is the video of Taofledermaus testing these rounds.



Here is the video John posted making these projectiles.



John will be giving away one “unfired” missile slug to one of his Patreon supporters. So sign up and you can enter to win a slug missile. Click here to go to the Patreon page. Or you can follow John on his Youtube Channel, CNC NYC.

Nicholas C

Co-Founder of KRISSTALK forums, an owner’s support group and all things KRISS Vector related. Nick found his passion through competitive shooting while living in NY. He participates in USPSA and 3Gun. He loves all things that shoots and flashlights. Really really bright flashlights.

Any questions please email him at


  • Reminds me of the Frag-12.

    • Budogunner

      I’d like a box of those, please.

    • Giolli Joker

      They should try to replicate it… quite likely that the fins are soring loaded.

  • TDog

    Hollow them out, add some propellant, and let ‘er rip!

    • Jay R Logan

      Or an explosive.

      • TDog

        Or both! Heck, we live in America! Let’s live a little!

  • Badwolf

    Looks like fleet yaw NathF talked about. Maybe needs more distance to stabilize.

    • Anonymous

      No, it’s not. Fleet yaw is a byproduct of a projectile spinning around its central axis, and we can see pretty clearly that those slugs aren’t doing any such thing. It’s not an effect that’s going to appear in a smoothbore.

  • BattleshipGrey

    I wish he would’ve tried to shoot a longer distance with the finned version to see what happened when it finally stabilized enough to get some air flow through the round.

    • Dan


  • iksnilol

    Thanks, but if I will use something really expensive in a shotgun I will use Hexolitt32.

    • jcitizen

      Ugh! I don’t think I have the guts to shoot the 32S toward any living being! Would be fun for Zombie targets though! 🙂

  • Kelly Jackson

    Reminds me of the bullet from Wanted

  • Brian Hert

    I wonder if they added a lead weight to the front and gave the round another 10 yrds or so to stabilize what they’d see?

  • Mike

    The twist rate is very abrupt and may stabilize at a longer distance but I see an issue where the design is good but might have been fighting against itself. The grooves that are cut to provide the twist to the projectile will encourage the projo to twist clockwise from the shooters view. The fins are assembled in a manner that will make them stay folded back against the projo, they might have deployed if the were mounted the other direction to take full advantage.

    • AlDeLarge

      That was my first thought too. But ignoring that for a moment, the air coming out of the holes, hitting the inside of the fins would cause it to spin clockwise and hold the fins open. If the force causing the spin is acting on the fins, it also keeps them open. Look at the beveled fins on the Frag-12. If the force causing the spin acts on the main body, it acts as you imagined.

      Those little spiral grooves on the body wouldn’t really do anything. Foster slugs have a bunch of grooves like that, and they don’t spiral. I can’t imagine the air jets would do anything but give the fins a little nudge at the beginning, though. It would be like trying to hit the car next to you on the freeway with a squirt gun.

  • gunsandrockets

    I suggest a slight modification to the finned projectile that might work better. Delete the fins and change the vent holes so they are off center, yet symmetric to each other. That might be easier machine with 4 vent holes instead of 3. The idea is for the venting gas to spin stabilize the projectile. Placing the vent holes nearer the center rather than the base of the projectile might also help.

    • jcitizen

      And while you at it, put a very small fireworks rocket motor into a chamber in the base to supply the pressure. Those puppies can stabilize real quick if built right.In fact just use one that already has the jet holes molded in it, and glue it to the base.

  • Ron

    Forget the air flow deployment. Hollow out the back and spring load the fins. Also slant the pivot pins slightly for more spin and forget the spiral grooves. They have almost no effect, since they are in a low pressure area.

  • Mazryonh

    That’s the Taser XREP round in the picture above the first video. This blog had a few articles about it years before. But Taser International discontinued it, despite the XREP’s potential.

  • Kivaari

    I suspect it would be simpler to just have small fins that standup with the desired spin angle already. The fins would not have to be as large nor elaborate, all erected by a simple v-spring.

  • Dean Iversen

    the biggest problem is the overall weight of the projectile vs design, when it exits the barrel it hits an even larger wall of air and since its being pushed from behind it wants to tumble.

    you want the weight at the rear until it reaches a safe speed where the the detonation power isn’t trying to push the rear ahead of the front, I would use a ball bearing inside the projectile with a spring mechanism that will push the heavy ball up front once a certain speed is achieved therefore making it nose heavy to maintain some stabilization?

    however spiraling will cure most of those issues then you could teflon coat it to relieve barrel friction and to slide thru whatever it enters?

    you also need a;

    high speed camera
    Plexiglas swim pool
    Plexiglas vacuum cage for zero resistance analyzing fro analyzing ballistic coefficient

    the high speed cam allows you to analyze data more accurately

    I can say right now you need to taper down some of the rear of the projectile ASAP so it can handle airflow better (drag), it would most likely perform better if you gradually tapered it front to middle then from that point tapered it to the rear

    designing self propelled projectiles is different than non self propelled, take a projectile that has the very same basic design then use your fingertips to project it, note how your fingers will push the rear ahead of the front causing it to barrel roll

    I honestly doubt you can reach supersonic speeds without rifling with that size, maybe try a smaller barrel size like 20ga?

    remember, you can always cut the projectile in half then hollow it out then tap and die each end to re-assemble it, that way you can reduce weight and add mechanics like spring loaded fins that if curved properly like a propeller can get it to spin for stability and payload.

    having a gun shop rifle the barrel is best bet for a combination of both, really depends on the velocity and distance you need desire?

    another way to insure your projectile does not flip over in flight is to put the center of pressure behind the center of gravity (fins and tepering) otherwise spinning along its longitudinal axis (rifling )is about the only way with a non self propelled projectile.

    note how a non self propelled arrow maintains stability using fins, its scale proportion is another crucial dynamic as well.

    Ballistic XLR
    GNU Exterior Ballistics
    Point Blank Ballistics
    Remington Shoot
    JBM’s small arms ballistic calculator

    there is plenty of computer freeware you can install that will aid in getting it perfect, remember to patent any innovative designs as well as focusing on payload…(where the $$$ is)

    if a projectile can be designed to handle small lightweight payloads one can patent a design to shoot samples of ones blood and other DNA out into space in the hopes that one day it can be salvaged and brought to life, ashes can also be shot into space for a deep space burial? just use your imagination

  • jcitizen

    I used to have fun shooting badminton birdies out of smoke launchers. Sometimes you just have to apply the KISS principal to make it work the 1st time.

  • Michael Willis

    I wonder if anything this complex is needed. Perhaps just a central shaft drilled from the nose toward the tail with three or four exit holes drilled sloping in from the rear and at an angle to the central shaft.