An interesting idea: Using the Magnus Effect to control the path of a musket ball

Magnum Effect

Greg from Canada emailed me an idea. He proposed creating a 360 degree rotatable musket barrel with cuts perpendicular to the path of the ball that would impart a spin on it. If a ballistic computer controlled the rotation of the barrel, the bullet could be fired in a way similar to the Angelina Jolie movie Wanted (2008) where bullets were fired at multiple targets by spinning them around corners.


Greg wrote …

I’m far too old to start tinkering with firearms designs myself, but
in listening to many years’ worth of talk about shooting around
corners, I keep coming back to a simple design using balls instead of
bullets, plus a special type of barrel.

In order to make this work with consistency, you’d need a setup with a
built-in range-finder, a built-in computer, plus you’d need a separate
spotter and shooter; the spotter for finding the target in
3-dimensional space, and the shooter who must rely on the spotter’s
information, simply because in many or most cases he wouldn’t have the
target in view.

The design of the interior of the barrel is what would make this
possible, and the barrel itself must be able to rotate 360 degrees.

Instead of rifling, the barrel must have parallel lines cut in a
straight line in order to put spin on the ball. If turned to the
bottom, the ball would drop like a rock. If put on top the ball would
gain hang-time depending upon the rate of backspin. If turned to
either side, the ball would drift to one side or the other in a
variable arc.

I tried this many years ago, with some pretty primitive equipment, but
it was enough to show that you can make a ball break to the right or
left. My buddies thought it was hilarious that I was able to make the
thing “miss the target” by such an extreme degree, and I couldn’t make
them see the possible advantages.

We didn’t have today’s high-tech range-finders or computers or CAD
programs or CNC’s in those days. If I was young and had it to do all
over again, I’d make something that could pick off an enemy soldier
from around a 40-degree angle; enough so that he wouldn’t know where
he was being shot at from, which would be a great advantage in

I was using a muzzle-loader back then, but substituting a ball for a
bullet in a shell isn’t a problem. Plus a hardened ball can do many
things a bullet can’t. The penetrating properties of steel balls are
very much unlike the penetrating properties of bullets. We found out,
purely by accident, that ball-bearings will pass through a pane of
glass without breaking it, whereas a lead ball smashes glass because
it flattens on impact. We also found out that ball-bearings will
penetrate thicker sheets of steel plate than lead. And if the bearings
had high explosive inside, that penetrating-power would increase

Anyway- thought you might find this interesting, and fun to try out
for yourself.

The downside of this idea is that it would only work for balls, not bullets, which are inherently inaccurate.¬†It also would be incapable of firing straight. It is easier to lob a 40mm grenade into the vicinity of the area that spray bullets around the corner of a building … but still, its an interesting idea.

Steve Johnson

Founder and Dictator-In-Chief of TFB. A passionate gun owner, a shooting enthusiast and totally tacti-uncool. Favorite first date location: any gun range. Steve can be contacted here.


  • mikewest007

    So, a hop-up system?

    • Nicholas Chen

      Ahh you beat me as I was typing it. LOL

  • Nicholas Chen

    This is Hop Up technology used in Airsoft Guns. There is a rubber speed bump inside the chamber that gives the BB backspin.

    • lucusloc

      Yeah, this works well enough at airsoft and paintball speeds, but a musket ball is going to be going far too fast to impart any significant arc. You may be able to hit someone a few inches behind cover, if the cover was roughly equidistant between the shooter and the target, but you would not be able to “hook” the shot around any kind of sharp corner.

      However, if you could get a very consistent spin on a suitably blemish-less ball this could improve the precision of the shots, making repeat hits more reliable.

    • Paladin

      And as one might expect, if you hold an airsoft gun sideways the spin will push the BB off to the side rather than generating lift. It’s not usually enough for anything so dramatic as shooting around a 40 degree corner, and it’s not exactly practical, but one could conceivably use it to hit a target without a direct line of sight. The real problem is how one might aim at a target they can’t see.

  • Alex D.

    Why do people keep calling steel balls bearings? It’s not a bearing until it bears a load, or at least intended to.

    • ostiariusalpha

      Yeah, not to get too hung up on technical terms, but they’re just called balls or rollers. They’re not bearings even when fastened by the cage between the races; the whole thing is the bearing.

      This is a ball bearing:

  • mechamaster

    worth idea to experimenting. For science !

  • Sianmink

    They’ve been using this in paintball for years.

  • Tippmann pioneered this with the Flatline barrel over a decade ago… Almost 2 decades.

  • Don Ward

    The illustration doth not contain the Demon ryding the Ball which doth affecteth thy aim.

  • Hensley Beuron Garlington

    My old Tippmann Model 98 with the Flatline Barrel system used a curved barrel to impart the same backspin on the ball. However, due to the seam between the two joined halves used to make the paintball house the paint, it would “catch” more air as it spun through the air. Because you couldn’t control how the balls fell into the chamber from the hopper, you had no idea how your next shot’s paintball seam was oriented in the chamber, so shots often veered off in any direction according to the way the seam was lined up when fired.

    Mine was slightly defective, I bought it used, so I could turn the barrel to shoot around cover. I actually used this blind firing method to great success, but it felt really, really stupid.

  • Rick O’Shay

    So…. tactical pitting?

  • ChristianC

    Couldnt this be done with rifling on the top on the barrel instead of cuts?

  • Dracon1201

    Look at the Apex tip for paintball. It’s the same thing. This tech exists as everyone has noted.

  • ganadharmabhasa

    Fascinating topic.

  • gunsandrockets

    Boy that is freaky. Still trying to get my head around the magnus Effect. Because for one thing it seems to create a force opposite in direction to the bernoulli principle.

    As far as a practical weapon system, I could see the possibility of exploiting the magnus effect for a low velocity weapon system similar to the 40mm grenade launcher. The benefit would be to balance out the lift generated vs velocity, to provide the effect of a much flatter trajectory projectile. Because the projectile is spherical, the bore of the magnus grenade launcher would be greater than 40mm to fire the same weight projectile.

    A flatter shooting grenade launcher could be pretty useful in urban combat. And a tricky gunner might pull off some oddball shots by firing the grenade launcher tilted to the right or left.

    • Cymond

      From what I understand, lift is not actually generated by the ‘Bernouli’ principle.

      • gunsandrockets

        Upside down doesn’t trouble me.

        An upside down plane can generate lift for the same reason a laminar flow airfoil wing can generate lift, by controlling the angle of attack. You might note that stunt planes which are flying level and maintaining altitude while upside down have a significant nose pitch away from the ground.

        • Cymond

          Honestly, this stuff is a bit over my head, but the fact that NASA disagrees with Bernoulli as the source of lift … that’s significant.

          I’m just arguing that the reality is far more complicated than what they told us about Bernoulli in science class, but bringing up laminar air foils proves you already understand that far better than I do.

          • gunsandrockets

            You are half right.

            You are right in the sense that the exact math and applicable principles of wing lift are more complicated than what is presented in High School introduction to physics.

            But you are wrong about what the NASA link says about the Bernoulli principle. The link actually says that the Bernoulli principle is the main source of wing lift. The problem is you kind of have to dig down into the meat of the article to see that. The article is a little too clever in how in phrases things.

            The main criticism of Bernoulli contained within the article, is that many people misunderstand how a wing surface is related to the Bernoulli principle or they apply Bernoulli to the math of lift generation poorly.

            I try to grasp some basic principles of ballistics, rocketry and airflight, but don’t ask me to do the math. My math competency is about the level of pre-trigonometry at best.

  • Mystick

    So…. it’s an airsoft hop-up. This is not revolutionary.

  • Hank Seiter

    I’m pretty hopped-up about this development. I wonder if there’s a way to convert my green gas-operated Wei SCAR to use .32 caliber lead balls (buckshot-size)? I wonder how the BATFE would classify that?

    • Cymond

      It would still just be an airgun. There are precharged pneumatic (PCP) big bore airguns for hunting.


    This is the same thing you (intentionally do when you put spin on a golf ball

  • Paul Labrador

    This is already what they do for airsoft guns, so nothing new here. But here’s the thing: who uses smoothbore muskets nowadays other than some historical re-enactors? And the magnus effect does nothing to correct the issue that musket balls are generally sub-caliber to the bore, so it’s still bouncing around down the barrel when it’s fired.

  • jcitizen

    Hmm? Say you have a barrel with rings all the way to the muzzle, and a ball with ridges only on one equator – then the ball could also have a free floating, but magnetic,(much like a motor stator/rotor) sphere inside, with a high pressure vessel, and/or chemistry firing chamber. A heat resistant chip would tell this free wheeler when to release a spurt of gas in one direction only when one of the ports was aligned. This would add a lot of English to the flying ball, as both concepts would be in force. With today’s technology, and a good shop, such a project could be easily attained. Too bad I no longer have a full machine shop with CNC controlled equipment at my beck and call any longer, or I would at least try to build one prototype. Ogive tolerances and geometry would help clearance on the counter side of the projectile ridges.

    The computer would auto orient the ball to the bore in the breech, as to the vector, then program the chip for angle of gas release. It would be more fun that a barrel of monkeys! Of course making smart bullets with high explosive fuel like the star wars program made for space interdiction may be easier. I love watching the test videos done in earth’s gravity!