Experiments in Magnetically-Delayed Blowback 

Did your research and calculations take into effect the expansion of the .22 caliber case when fired. Years ago I had a 10/22 and in trying to "customize" it, I polished the feed ramp, breech, and all the bolt faces. I put a mirror finish on all those surfaces. It was beautiful.....but shooting it revealed that blowback gasses were blown right into the face of the shooter My polishing job had altered the lockup time because the case would expand into the polished surface , it could still propel the case backwards. The case and breech was designed to have the case swell and grip the inside of the breech....and then when the pressure dropped the case would release and the case could push the bolt backwards, cycling the action. It racked my 14 year old brain for about a month until I took the gun to a local gun shop with a gunsmith. He laughed when I told him what I'd done and took me into the back. He disassembled the rifle and took a piece of 800 grit sandpaper, put it on a loose mandrel and ruined my meticulous polish job in the breech. After he got a "satin" finish in the breech he reassembled the rifle and took it over to his test stand. Set it up and loaded a round into the chamber, and put another round into the magazine and put the magazine into the rifle. Using a hook he then pulled the trigger, it went off......but no blowback gasses! Same with the second round.... My rifle was fixed! He explained to me what I'd done and the effect it had on the action.... He charged me a whole dollar for the repair. But the lesson was learned.....

Nobody ever posts videos of projects that did NOT work, but you can learn so much from failures. Plus this is very entertaining and informative aside from your project. Thanks man, keep 'em coming!

One problem I see is that the point of a blowback mechanism is to stop the bolt moving any significant amount in the microseconds the bullet is still in the bore yet for the eddie currents to be created the magnet on the bolt needs to move a significant amount. I think the best use of magnets is as a buffer to more smoothly decelerate a high velocity bolt in a short receiver, as that is the point a bolt will be moving the fastest and needs to be slowed down smoothly.

My first thought is that you need an accelerator, like in lever delay, that uses leverage to push the block with the magnets faster than the bolt itself moves back. This would let the bolt stay largely in place until the eddy currents could form, and it would be stronger because it could go faster. But at that point you essentially have a lever delay rifle already and im not sure what advantage adding magnets would have.

Gilles, as a fellow tinkerer and firearm collector/gunsmith I would like to say you never cease to amaze me with the depth of your knowledge about so many things.

I'm surprised a channel this professional and nice is so small. You need more subscribers lol

I wonder how much effect there would be if you had a magnet on the bolt and one on the frame that were almost in contact when the bolt is closed and pull towards each other. As the bolt moves rearward it would provide some amount of resistance to the initial opening but would drop off quickly as the distance between them increased.

Some of my most enjoyable learning experiences have been otherwise fruitless excursions down a dead-end rabbit hole like this one. Cool video. Thanks.

@6:59 Guys, go to Forgotten Weapons and check out Thompson's 30-06 semi-auto Rifle that competed against the Garand! It was designed using an actually nonexistent notion; the "Blish Principle." Long story short, it ended up being a blowback 30-06 rifle that ejected cases so hard they would stick in boards placed next to the shooter.

I have now seen multiple videos from several different RU-vidrs attempting to use magnetic breaking in different applications that commonly use mechanical means. Every single time it proves to be ineffective or impractical in comparison to mechanical breaking.

Very interesting presentation. Almost all new research projects have a very high failure to success ratio, but the knowledge gained is worth the effort. 👍👍

I am extremely impressed by your video. Very well put together in a concise factual manner. The information you provided was extremely helpful. Thank you for a job well done.

I have to say, I'm impressed with your ability to very clearly explain these mechanical systems with clarity that allowed me to very easily understand what you were saying. Great video! ('86-'94 CAF MOC R421) Arte et Marte!

It’s such a fun idea, although in practice if this worked the heat generated would affect the impedance of the metal and change the magnetic properties and reduce its effectiveness after a single shot. Also the magnets would probably be destroyed from the heat. Also the mechanical forces are an order of magnitude greater than the force you can create with such a small area of interaction, so the equations don’t work the way they’re academically taught. There are limits to the size and behaviour of the eddy currents in a given volume of material. Also the phase delay in the field being generated probably means you won’t see anything meaningful from Lenz’s law in response to an impulse like an explosion. I look forward to future experiments though

Nicely done! A great explanation of testing theory and assessing results. I am enjoying your series of videos for their engaging detail and as a transplanted Canadian with a keen interest in the mechanics of firearms this title certainly caught my eye. Thanks!

Makes sense. You need blowback delay at the beginning of blowback, but eddy currents don’t develop until the slide is already moving fast.

I made a magnetically locked gun, it just uses a solenoid to engage a locking bar. In the future, I will have the unlocking done automatically based on either time after ignition, or chamber pressure assuming there is a pressure sensor with high enough response rate.

Did you consider arranging a series of thin Nd magnets in a Halbach array to maximize the distance and field strength at their braking surface at the expense of nulling it out on the opposite side?

Brilliant!

I too have seen the King Cobra video, with their 3D printed frame it seems that their system may be more of a continuous recoil system in that the claim is made that it is softer shooting, and when the magnets are removed the system still functions. A magnetic buffer for machine pistols may be what you have.

There's still a lot of potential here. In particular reducing felt recoil by preventing the bolt from sharply impacting the back of the receiver without needing a ridiculously long recoil travel and spring. And generally making a short receiver with a light bolt behave like a long receiver with a heavy bolt. Potentially making an LMG receiver in an SMG receiver's form factor could be more important than yet another unlocking mechanism, even if it's an elegantly simple one.

Thanks for sharing! I'd had the idea for a magnetic delay system about 3 years ago just fiddling around in my head, I'm glad someone actually pursued it and their findings were here for me to recalibrate my thoughts about eddy currents! I still believe an equally simple delay system is waiting to be found though, without gas ports, rotating bolts, rollers, levers, etc... It's out there somewhere, waiting to be found.

In short: Too much delay in the delay.

My first machine gun was angle delayed-blowback, a Reising m50, fantastic on the range if not on the South Pacific beach.

Connect the bolt to a circular mechanism that results in a long horizontal travel. Allow that travel to occur in the rifle stock. That will allow 9" minimum of horizontal travel. You could also permit the travel to be in a tube, reducing magnetic flux losses.

I know its not the same thing, but it reminded me of the Blish lock system used in the Thomson submachine gun.

I use neodymium magnets to delay the blowback of my AR9, they sit on opposite sides of the bolt, I think they work better if I machined the spots where I put them to get them closer to the bolt, you can tell the difference with them on and off

I thought about doing a magnetic delay system for the Ruger 10/22 as well, back in 2017. I got the idea from a guy in Minnesota who designed and marketed a magnetic recoil buffer spring for ARs. Don't recall the name of the company. My design was to incorporate several round neodymium disk magnets on the sides of the bolt as well as in the inside surface of the receiver. The magnets would line up, positive to negative, either complete contact or a slight space between them. After sharing my design idea with this fellow from Minnesota, I cancelled it when he said it wouldn't work and gave me a pretty convincing technical explanation of why. I haven't seen my idea appear anywhere in the gun community, so I trust he was right.

Awesome video. I loved the explanations and the thinking processes and how your team implemented them. Thank you.

Absolutely fascinating. Your experiment was worth the gain of knowledge and you passed that knowledge on to us. This wouldn't involve your eddy current idea but I suppose a bolt could be held closed electromagnetically until the gas or recoil broke the connection and allowed the bolt to move back.

Sounds like a good idea as a replacement for a buffer system

I salute this brave R&D endeavour and the way you make it a learning experience. Clear negative results make science progress !

Nice video, and that's an interesting design! At the beginning of the video, I was thinking that your description of how eddy-current braking works (namely that the counter-force generated is proportional to the velocity) meant it would be unsuitable to a delayed blowback system. Such systems need the delay to happen when the velocity of the bolt is at 0 or near-0 (ie. while the bolt is still in place and sealing the chamber), not when the bolt is already in motion after unsealing the chamber. In short, it sounded like the system would produce the least breaking when it matters and the most when it doesn't (or even when it could become counterproductive, depending on the recoil spring). I got a chuckle out of the description of that very problem at the end. That said, I wonder if the same principle might not still be useful in longer-stroke rifles to cushion the perceived recoil by bleeding off the bolt's velocity before it impacts the rear, and magnetic linking might be useful to designs trying to maximize separation between the firing mechanism and the combustion gasses. Also, it's funny how many common technologies boil down to setting off contained explosions...

Just what I expected. Any electrical engineer with generator experience would have told you that velocity is needed to generate the force. Your little ramp shows it simply. It accelerates quickly then when moving fast enough stops the acceleration. A lever system that moves the magnet through a much longer travel than the bolt would accelerate the magnet much faster. Put the magnet system in the buttstock with a 10 to 1 lever on the bolt.

Thank you for making this video! I had a similar idea earlier this year, and I was quite confident that it would work. Your insight has saved me a great deal of time. I'm glad I found your channel. Sometimes the youtube algorithm picks you a winner!

One of the main disadvantages with this delay concept is that permanent magnets 🧲 lose strength at elevated temperatures; alternatively you could use battery supplied magnetic source would not lose power but would be a pain to rely on batteries.

Probably the most engaging and fascinating episode of Forgotten Weapons that never was.

I was gonna turn this video off, and then i saw the mas and realized you are a man of culture.

❤ Awesome Sciencing! I sincerely believe that more is often learned from those sorts of projects than less challenging ones

Your idea may work in conjunction with advanced primer ignition. Magnetic braking can stop/slow down an object in motion but not an object at rest. If the bolt or a linear hammer was used for API this idea might be helpful.

Working out why some assumed solution to a problem DOESN'T work as expected can provide a greater insight into a subject than 100 "Worked straight out of the box" scenarios.

Absolutely top tier content here. Not only are you sharing novel ideas...but you were not afraid or ashamed to say that your idea failed (not to mention breaking down exactly WHY it failed). This is not seen very often, and most people dont understand just how much of a positive impact that makes as a whole. If you did a collaboration with Ian at Forgotten Weapons, I think that'd be mutually beneficial to both channels. You are similar in the professional style of video structure, you both bring excellent ideas and both make great points on everything you cover. I'm sure you are both extremely busy individuals, and it may be difficult to do so, but I think it would be the most watched and most informative video either of your channels have published. Don't take that the wrong way, because I you and Ian are now my all-time favorite channels

I've watched zillions of gun videos and never heard such a great description of how/why blowback is avoided. Ty!

Surely the first experiments should have been to examine the fields created

So glad youtube recommended this video, and that you shared your results. I was just considering this idea.

What a fascinating account! Nicely done, my man.

I tend to take an exception to a researcher who states that a project failed because the hypothesis (or hypotheses) turned out not to work for whatever reason. Every research project taken to its conclusion is a success, regardless of "positive" or "negative" outcome. In either case the researcher(s) proved something, which was not proven before. In a way, one can compare research projects to a blood test: NEGATIVE - great, you are healthy (or there is a need for more tests), or POSITIVE - great, now we know what's wrong, and we can start working on curing whatever it is. I like to think that there are no failed research or design projects, there are only successful and abandoned ones.

Only problem I can see is that the eddy current braking is dependent upon relative motion between the magnet and a conductive [aluminum or copper] substrate, while the *prevention* of relative motion until the critical period is past and the barrel pressure has subsided is the necessary attribute of the breech.

Guns are the coolest things to experiment on. Why not try attaching a rod to your bolt like a gas piston with magnets up front in the hand guard to add more braking force. also you could put a south pole facing magnet on the bolt and a north pole facing magnet in the rear of the receiver to act as a magnetic buffer

That 1911 looks... Let's call it well-loved

One of my favorite blowback designs it the oerlikon 20mm aa gun. It uses a rebated rim and advanced primer ignition to allow a 20mm cannon to fire from an unlocked breech. By igniting the primer while the bolt is still traveling forward the cartridge must overcome the forward momentum of the bolt before the chaber can open.

Your channel is like Technology Connections and Forgotten Weapons had a baby. I love it.

This was an awesome video to watch and had me enthralled the whole time

Totally awesome stuff I'm quite a fan of the variety in actions.

The joy of experimentation is that you get to learn something new. I loved doing experiments in grad school because you think it is going to behave this one way and sometimes it does but other times you get the exact opposite and then you get to figure out why. That part of grad school never felt like work.

Sounds like it could've worked *better* with a long-recoil action, that'd've been interesting but very difficult

There's an interesting piece of software called QuickLoad that gives you the pressure curve over time in a given barrel from a given powder load and bullet weight.

This video is extremely interesting and well put together.

Interesting! Good work! You often learn more from "failure" than from success!

Another thoroughly fascinating and easy-to-follow interview. Thanks so much.

Fantastic. My old Thorens TD124 turntable uses an eddy current magnetic brake for speed control. An ideal application.

I too have pondered how to delay breech opening, so this was most interesting. What is needed is an inertia multiplier or at least something that works like inertia.

Even though it didn't work out, I'm sure you had a lot of fun in the attempt and learned a lot along the way too.

Not every self loading firearm has a mechanism to slow down the action. Many smaller caliber firearms from .22short up to .380acp are simple blowback operated firearms with no delayed mechanism. That's also true for many 9mm firearms and even some .40'SWs and .45ACP's. The Hi-Point firearms are all straight blow-back if I'm not mistaken,. I think even the .45's and 10mm's are too... and most of the older 9mm SMG's are also (Uzi, Sten, MAC, Sterling, Thompson and many others). Many are in .45acp too.

magnetic braking would be a better application for slowing down a lightweight bolt on, say, a gas-impingement system or ar15-style gas system where you want a lightweight bolt, but you also want "overgassing" for adverse condition operation or suppressed shooting. You would use the braking effect to slow the bolt velocity down before it slams into the rear of the receiver/buffer tube. You get something like viscous damping from the braking system. if your standard damped oscillator is m*a+c*v+k*x = f(t), then bolt/buffer mass, m, and spring weight, k, are typically there, but you can add the viscous damping, c, with eddy braking. the point is, "c" can't replace "m" in the physics

This is so cool I cant wait for Ian's kids to do a video on this in 50 years.

In less than a minute i have become completely hype for the idea presented and i want one for its unique mechanics

I think the first answer lies in electromagnets and solid state relays. One on the front to keep it closed, one in the back of the receiver, and some solid state electronics to turn each one on when it's it's time to work

Okay. I'm glad I started following this channel. This was very fascinating. I'm halfway wondering about piezo modules to induce an electromagnetic charge. But, this is far outside an field of expertise I have. Still, I'm glad you showcased this design. Even if it didn't work, it only means that this particular approach didn't. And it still produced valuable information as part of the process.

Great video! Thank you!

Like T. Edison said, I have learned 999 ways not to make a light bulb....

Fascinating! Thanks for sharing your research on this.

Fascinating! Very interesting idea and glad you tested it.

The 3d printing ppl are using magnets for blowback operated pistil caliber carbines. They are adding magnets in a series to the receiver to slow the recoil of the bolt a little bit.

Thanks for the detailed explanation. I wondered if a mechanism like this could be used for an automotive shock absorber. This rules it out for me because of the lack of initial resistance to movement that i was not aware of

I have an idea, on the slide of a pistol would have small pneumatic pin and would slot into a socket which has an adjustable air bleed screw to delay the blowback and another pneumatic pin on the back end that's unvented, this would cut down the metallic clunk when using a suppressor, biggest advantages are a full burn for the bullet to leave the barrel the adjustable air bleed screw would allow full blowback on low or high velocity rounds and a quieter operation

Great video and a great idea.

High power cartridges require discreet locking & unlocking as even a partial premature extraction will see side wall ruptures of the brass. Where I could see this being useful is as a buffer at both ends of the cycle to delay the bolt allowing extraction & cartridge ramping from the magazine but more importantly to mitigate the bolt's impact of the end of the receiver which causes muzzle climb & the bolt impact with the breach upon closing which causes a bolt bounce as seen in the Rugger .22 slow mo & muzzle drop. Kind of a magnetic version of the Scorpion machine pistol which would allowing for a short receiver, with a slow the rate of fire, a steady force cycle that would mitigate the negatives of the open bolt cycle on assault style weapons.

Very good. Nice to see an experiment gone wrong and such a good explanation.

Interesting project! I think the biggest problem was using 22LR. Very little bolt mass is required to generate high pressures. I'm willing to bet the gun operated fine even with the lightened bolt. Using 9mm, or ideally an intermediate cartridge like 5.56 would generate the higher velocities to maximise braking power.

Not gonna lie, until you pulled up that Moss 49, I had no idea it was there, so smooth transition m8y

This was super interesting. Thanks for making this video. I was introduced to the eddy-current braking effect in college, where we used a spinning aluminum disc, slowed by magnets for labs in system controls. I thought, there must be another application for this effect.

You had me at "magnetic eddy current delayed blowback system"!

When you originally said that magnetic resistance of the eddy currents is directly proportional to the force applied, You showed the error in your hypothesis of your design. I have a patented braking system for zipline trolley wheels that uses eddy current braking. While testing various configurations, I realized that the resistive force of the magnetic field is directly proportional to the differential speed of the magnet and the di-magnetic material, the conductivity of that material, strength of the magnet(s), distance between the magnet and di-magnetic material, and if multiple magnets are used in series, alternating their polarity also increases the resistive force. I think you could have made your system work if the bolt entered the breach for about 3-4 cm allowing the bolt to accelerate rearward while still holding/keeping the chamber pressure sealed. This is only when the eddy current resistance would be available to delay the ejection of the spent casing. This project is a great example of how, what we think we understand might be possible theoretically or scientifically, from our education, is often wrong, and thus scientific laws are not accepted and 'settled science' until it can be repeated anywhere and anytime, as a result just because something works in one situation does not mean it will work the same in even a similar situation. I have learned there are very few situations where science is settled, Science is observe, record, report. Education only helps us understand more of what is happening in our life experiences, and it is only during and after those experiences that we truly learn and understand how and why the science we studied works, but also, often more importantly why it didn't work. But only if we are open to the idea that we could be wrong.

Great stuff!

I never understood the excitement for this type of idea. A spring is such a simple thing, not much can go wrong. Trying to use magnets overly complicates it and brings in multiple potential sources of failure. You can't get much more simple and cheaper than a spring....

Nice test and trial. Hope you come up with more ideas and test them.

Fascinating!

Thank you. Excellent. Good explanation of system. I never thought of your system. Listening to your channel

11:32 As a United States viewer I can't help but be in awe that with the draconian civilian-disarmament laws of our northern neighbors you're just casually flashing a (presumably) un-papered SBR on the internet. That aside, thanks for the walk down memory lane to my college (university) physics classes!

As a longtime fan and gunsmith I have no idea how I missed this in your back catalog. I’d like to see you tinker with inducing current from the bullet traveling down the barrel and using that to initiate and unlocked sequence.

A gas delay action uses gas to hold the action closed. The hk p7, Walter ccp, and styer gb are all examples. The tap gas from just in front of the chamber to pressurize below the barrel (around with the styer). That gas acts on a piston attached to the slide and prevents cycling till the bullet leaves the barrel, and the pressure drops. Then there pistol cycles like any blowback pistol. The mas is a locked breach, it uses the gas to move the bolt carrier. The movement of the carrier is the only way the bolt unlocks.

Love your format and delivery of information. Keep that shit up!

That building magnetic field is observable when you drop a pendulum against a copper plate

That's funny, i read the title of video and immediately got two sentences in my head: 1) They're trying to use eddy currents to delay simple bkowback 2) It won't work, the opposing force is proportional to velocity not the input force, this need a secondary mechanism to delay it _while_ it gets up to speed, at which point you've either overcomplicated it is added enough mass that you might as well stick with inertia delayed blowback. And I'm not an engineer or anything, I don't know any of the maths and I couldn't tell you how or why I came up with that. I guess I've just heard bits and pieces over the years and my brain jammed some factoids together and solved a problem. This often happens to me and I have no idea why. If there is a solution, it's tweaking the maths so that the opposing force needed is generated at a certain velocity that's reached as close to instantaneously as possible. Maybe a spring, or springs, that has/have variable spring force depending on the bolts position and velocity. Maybe it could even be as simple as two springs, one long, thin and weak inside one short, wide and strong. So fast bolt acceleration at first, slowed by magnets and then caught and returned by the short and strong spring? Or maybe just even a weaker spring. Next I would look at the force/velocity relationship and see how varying the geometry (or even variable geometry?) of the magnet/metal affects it.

Your channel is amazing. When i start making more than 9k a yeay i will support you financially. You have taught me so much that i feel that it is the least that i could do. Thank you for making the collective intelligence of the world a bit elevated.❤

Verrry interesting, thanks for sharing.

That's a concept that sounds amazing on paper but i could only imagine the horrors of trying to keep a rifle embedded with rare earth magnets properly clean in the field.

that was very interesting. thank you for sharing.

1:00 I got exactly what you meant and what a great idea! 👍 It's a shame it didn't work out.... seems like such a great idea and I bet, with the proper funds and time, you would be able to work out any issues!