What causes Pellets to Spiral? | AB101 pt. 11: Precession & Nutation 

I've been shooting airguns for 51 years, and found that I have shot better groups 40 or 50 years ago than my groups of recent times. During my school years I was the best shot in town with an airgun, but today I can hardly get two out of 5 shots close together. I believed it was due to old age or poorer eyesight, but now I realize the speeds I am shooting at is 50% to 80% higher than with my old Diana and BSA airguns. This video is the best information on the subject that I have ever seen. Thanks.

Shoot your slugs fast, shoot your short pellets med, shoot your long pellets slow, watch and learn. Glad Gregor got a mention, saved me doing it. opp's, mentioned him anyway, ah well He is well worth it. thank you Matt, always an education.

Just seriously informed, I am an Engineer and so impressed with your grasp of ballistics.

To think i had stopped watching you because you walked on this series. Then to see what you have been doing for us!!! Wish you tons of luck with element.. Sad a epidemic was needed to get you the time for this. Stay safe Matt!

There is no doubt that Matt is one of the most knowledgeable persons on the planet in the world of air gunning. There is no doubt that all this knowledge has it's benefits. But I'd be willing to bet that if you were really good friends with him, and asked him really nicely, he would whisper in your ear. "All I can tell you is that you have to experiment with your gun: different weights, diameters, power settings, ect, ect until you find the "thing" that works best for ...YOUR GUN! (I.E. - he can not tell you what "set-up" is going to work) P.S. The "trial & error" is the fun part!

I would just like to say thankyou Matt, for making all of your videos and series. I've been recovering from a total left knee replacement surgery since Jsnuary and I've become a huge fan of yours. It's been awesome to watch almost all of your videos of you hunting and showing of your beautiful country with the majestic animals. Thanks again for the videos Matt, you inspired an Army veteran who at the age of 49, is coming to terms with having a major part of my body replaced and I look forward to seeing more of your hunts. Bye from Canada.🇨🇦

Totally changed my outlook on 50 yard shooting. It's all about finding the power for the pellet not pellet for the barrel.

A awesome video Matt. I would like to share this info with you. I have a HATSAN carnivore in 35 caliber. I started using the h& n grizzly slugs and they were great out to 50 yards. At 75 yards a group was non existent. I switched to some jsb pellets and at a hundred yards it was a tack driver. The jsb pellets were traveling around nine hundred feet per second. The h&n slugs were traveling around 824 feet per second. That to me was a big difference with only one grain difference in the weight of the ammo. The h& n grizzlies were 82 grains. The jsb pellets were 81 grains. I decided to push both ball through the barrel. I noticed the jsb had light twist rate on the skirt. The h&n slugs had heavy deep rifling marks around the slug. I put the inaccuracy down to the fact... That the h&n slug was too big for my barrel. Ballistically it's still didn't explain to me why it was spot-on at 50 yards but at 75 yards it opened up to a 12 inch group. This information is not recent. This information is 5 years old. I realize things are a little bit different now and air gunning has come a long way and things are becoming more compatible... but I believe this is still useful information for those that seek knowledge. The one thing that has always intrigued me and also frustrated me is the amount of variables when it comes to the shooting sport. I was strictly a powder burning guy before I became an air Gunner... But learning about air rifles has been such an education and completely help me be a better Marksman all the way around.

Couldn't have fathomed all this without this video.. always wondered where my pellets flew with my unregulated airguns . Thank you once again! Love from Nagaland.

Matt Dubber is a wealth of information! Like many, he was my inspiration to become a RU-vid content provider! Keep up the good work!

I tried to get H& N to make a tubular design of pellet. Peter Schmidt looked at various designs but ultimately they chose to go with the conventional designs. I have found that pellets fired from a 12 foot pound rifle chronograph faster fired backwards ie skirt first, than when they are fired forwards ie nose first. They also expand very well at close range. I have not tried them at 25 metres but around 8 meters or so. I suggested in an article, I got published in 1976, that a projecting guidance point might help pellets travel straighter in tissue. A number of years later an America company made their bullets expand with the guidance point feature. I believe it was Federal Hydra shok. Strangely all bullets and pellets are sub-sonic after they strike gelatine, water or live tissue as they become sub-sonic in that medium. The speed of sound in water and other water saturated materials is always much higher than it is in air, so bullets are always subsonic as they penetrate game or gel or water. Nice video.

There was another air gunner touching in on this issue too with his lothar walther barrel, he had an issue where the barrel was out of spec in various ways, not only crowning and chamber were not up to scratch, but also air nozzle placement was a tad out of spec. He investigated further and found that also the inside of the barrel was burred, so he was getting pellet spiral despite weighing the pellets. It's assumed that all of this was what was contributing to pellet spiraling. When he wasn't getting pellet spiraling he was pulling long range shots, smacking pigeons from distances where they were almost a blur in his scope. I'll look for this channel, very valuable content that we could all learn from and I hope it hasn't been deleted or removed yet, I believe he even follows this channel.

Further comment you have really hit the nail on the head, accuracy and projectile speed are intricately linked.

Nice job Matt. The airgun community, (especially FX) is grateful for all of your work and dedication. And to think it all started with a fun, successful hunting outing when you were a boy.

Great video Matt. There’s an alternative theory you might want to consider: Chaos theory. Whenever you have a system that involves a number of factors contributing to the stability of the system, (in other words, it allows you to predict the outcome of a small change within the system) if one or more of the factors has squared or cubed relationship, at some unpredictable point changes to this factor causes the system to become chaotic. In the case you just described, using a middling software might be helpful. it’s probably helpful to examine various factored like, rate of change of energy, change in ballistic coefficient, or rate of change of velocity using the modelling software….

I love these videos. Like this is better than any sort of tv. The content and quality is incredible. Nice work.

This video answers so many questions I have been pondering on for years. Thank you for all the work you put into this.

After watching your series it begs me to ask the question of “when using your air rifle for dispatching pests or for hunting game, why would anyone want to use anything but slugs?” Don’t get me wrong because I have dispatched plenty of pests with pellets but with the longer shots approaching 100 yards, I used to get really upset when my pest was not hit in the area that would cause immediate death when I knew that I had zeroed in my rifle. I appreciate the time you have taken to explain the aerodynamics associated with and affecting the movement of both pellets and slugs. Please keep up the good work!

Knowledge is power!! Thanks for the great info.. Even if i have to watch it a few more times to soak it all in great job!!

Brilliant, not sure if you read these comments and if not that's understandable but in the slight case you do, please have a video explaining how climate/temperature/pressure affects PCPs. That I think would be perfect. As we all shoot in such different places.

Uh oh. This information is making my mind spin. Oh no! It's precessing out of control! Your video is an excellent external force to make me think. Thanks. Jess

you are a natural teacher..being curious is perhaps the most important trait a human being can ever experience. teaching is definitely your natural skill. Do that and you will never have to work another day in your life. God Bless America

I didn’t know that what I thought was precession was actually nutation, so glad to learn something new

15 minute video on pellet stability in air? Hell yeah!

Thank you for another excellent video.

Superb video Matt. Thanks. My limited experience of the phenomenon came shortly after watching an American talking about it - not Ted, but I forget who. My heavy pellets were corkscrewing at longer distances so I switched to a lighter pellet and the problem disappeared. My theory (or that of the American) was that my heavy pellets had insufficient spin for the speed they were travelling and the lighter pellets overcame the problem by going faster. This was shooting an HW100 .20 at around 11fpe, the heavy pellets were JSBs at 13.7grn and the lighter ones FTTs at 11.4. How great it would be if more slugs come out! I'd love an 11grn .20.. All the best.

Yes, awesome, this is a nice break from hunting with slugs. Not many of us shoot the open plains of Africa with little need of back stop. Mat, back to your best.

Back in the Early 1970's as a teenager I saw an AD for Sheridan Pellets in a magazine, not the Silver or Blue Streak Rifle, just the Pellets. I shot Black Powder Rifles as well as other firearms and BB & Pellet guns. But when I saw those 5mm/.20 cal Pellets that reminded me of a Black Powder Maxi Ball vs the crappy Daisy and Crosman pellets myself and my friends were using in our Powerline 880's and Crosman 1400's & 760's, it made me have to find out just WHAT Pellet Gun shot those things. A month later I owned a Blue Streak and got TEASED by the guys who had .22 pellet guns. Ugh...lol But once we went out hunting that changed real fast. ;~) Here are a couple of links to Pictures of the Sheridan Pellets "I SAW" in the AD at that time and what they look like, classic.gunauction.com/search/displayitem.cfm?itemnum=7236797 and here is an Older Packaging of the same design for a another view of them www.worthpoint.com/worthopedia/vintage-sheridan-ammunition-tin-5mm-20447089. I posted those Picture links for readers who may not know the ones I'm referring to since they did change the design of them at some point. Ok, back to my point of this post in regards to the Video. Those Pellets were basically Mini Slugs and they were DEADLY as well as DEADLY ACCURATE. I was making one shot kills with that rifle and those pellets that we only thought possible with our "real" .22 rifles. I knew back then that it HAD to be due to those Pellets and That Rifle being designed to work specifically with each other. If you look at those pics and see how they have the CONE on the Inside of the pellet and that the pellets were pretty darn clean/smooth and uniform compared to regular .177 or .22 cal pellets by Daisy and Crosman back then or especially today. It was tough to crush/deform those pellets on purpose prior to shooting them, so no worries to put some in our pocket or if the box got dropped. They were 2/3 SOLID and just the back 1/3 open. Manual said to pump it only 8 pumps, but I tested it up to 15 and found that 12 was the magic number for that rifle. It seemed to empty the cylinder completely at 12, but not at 13 to 15. So 12 pumps is what I always shot it with. So, after all of that my question here is why can't we get THAT DESIGN in a pellet now?!!! It seems to be a perfect "Hybrid" for today's more powerful PCP's. Not a Pellet and not a True Slug, but seems to have been the PERFECT ammo for the Sheridan Silver and Blue Streaks that were the most accurate and powerful off the shelf rifles at that time. Those pellets were virtually "Deformation Proof" before getting shot. P.S. If anyone knows of a Modern Pellet being produced in that shape/design, by any company, please post a link. I'm looking into making my own molds. Ugh..Grr...lol

A friend and I were having a discussion about the phenomenon just yesterday. Thanks Matt, useful info.

Good job Matt! It is a fascinating subject. As a benchrest shooter (6ppc over 100 and 200 yds) we look carefully for any indication that the bullet has passed through the paper out of perpendicular. When we see a bullet hole that is out of perfect symmetry we know for sure that load will not group. It is pretty neat that we can fire a single round and know that our load is right or wrong.

Good observations!

Hi Matt. After writing a whole paragraph explaining why your theory is flawed, I again carefully looked at your explanation. You could very well be correct, even if some of the information is "factually incorrect" the way you explained it. (That was what triggered the initial paragraph). So, there is a way to prove your hypothesis: As according to your hypothesis the wobble is caused by the bullet following a "curve" but trying to stay pointing in straight line. This "force on the back of the skirt" (as the pellet drops) is what starts the wobble, and YES looking at Precession it then makes sense as the "correcting" force is not acting against it, but 90 deg to it. Sooooo, if you were to shoot that pellet "vertical" that "lifting force" on the back of the skirt won't be there as the pellet travels in a straight line..... If that same pellet has no wobble in the vertical, then I think you hit the nail on the head !!

i had this with a few of my airguns, i was told on a few well known airgun forums that it was an optical illusion (you know the types.... think they know it all's) despite 6 other people who were behind and to ether side of me saying they were seeing the exact same thing. Tip crossman accupells are the best to see the spiral as the flat part inside of the skirt is like a mirror, best when the sun is behind you. Bisley magnum pellets used to be off center when you rolled one on a flat surface and watched the center line (front to back) and they spiraled a lot in a number of airguns i have seen. its impossible to say with absolute certainly what courses pellet spiral, there is a thousand and one variables, a pellet which spiraled in my gun did not spiral in another gun (both Falcon FN19 both producing 11.8 foot pounds) in the airgun community at the time when i was seriously into air gunning, it was known that you have to try every pellet you can to find the one that your airgun likes, i have seen on multiple occasions 2 guns with following serial numbers (they came off the production line one after the other) and they both like vastly different pellets (one likes the marksmen pointed pellets out of the little cardboard box, the other liked logun penetrator pellets) i think its a combination of many little things like the pellet been slightly off center, the lead alloy been softer or harder enabling it to form into the rifling better/worse (the antimony in airgun pellets will make the lead alloy age harden) the skirt of the pellet might have a slight defect, the power of the airgun been too high or too low for that pellet, ect,ect.

great info matt! delving into the "why" pellets spiral is a worthy subject. good hunting!

i LOVE this entire series, Thanks Matt!! each episode is so rich with information, i find that i have to watch each one several times to let all that sweet information soak into my brain... which i don't mind at all!! ;)

Awesome video always Matt. Thank you for the follow up. I have been testing this out between slugs and pellets. Keep up the awesome work.

Really good video Matt! Thanks for your hard work, time and effort to put all that info into a really accessible format. Keep up the good work and hope all is well!

Just binge watched this series, amazing info well explained !

You’ve articulated this issues, the possible/probably causes in a logical and well thought out manor. Thank you for the time, energy and effort that when into this video.

Hi Matt. Great explanation about this more or less problem !! I shut the "Monsters" both in my .177 and .22 HW 77K´s about 17-18 fpe No good ,No good ! From 40 yds I couldn´t hit my garage door !!!!!!! All over the place. I thought I will use this guys for FT challenge so I let tune those down to sub 12 fpe and guess what accurate to 100 yds( 3" target with the .177 ), in sub 12 and using the 13.43 gr. and a lot of hold over :))

What an incredible depth of knowledge! Thank you so much for sharing your experience 🙏👍

That was one of the most interesting and educational videos I have seen in quite some time. Thanks !

Thanks for doing all this work Matt, I know what time it takes to prepare a good lesson. I have really enjoyed watching it and have learn't heaps.

Thanks for the great, informative and thought provoking content Matt🤙

And that my friend was a wonderful video, very very informative, thank you so much.

Excellent production covering physics of air gun ballistics

Just a thought (based on an older video of your's) : When trying to shoot very fast a diabolo shaped projectile, you use higher pressure blast of air on the back of your pellet than usual, the "cup" side , thus this higher blast may turn around the pellet just as exiting the barrel. This may oscillate the projectile until the shape forces to finally stabilize. There are 3 ways to solve it: 1. Shot at lower speed 2. Shoot with air stripper, which deflects much of the blasting air aside thus refusing the pressure on the cup. 3. Shoot the pellet reversed, the blast will flow around and keep the pellet centered. I don't know if makes any sense, as said these are just thought triggered by your very interesting "balistics" videos, always a pleasure watching them. Thanks for your info you provide us with your work.

"SUCCESS FOR YOU MATT DUBBER " From indonesia 🇮🇩

I own a little break-barrel Diana #21 or so in 0.22 and warch your videos to learn and pleasure. For me, you explain very well and I understand quite easy. Thank you.

Ya I've been wait sence those videos. Maybe 2013 ish. You and Ted have given us some much info we all don't get the trial-and-error full experience. Thank you

Well done Mr Dubber, i have learnt a lot just by you explaining a few things. .Thank you

Really interesting subject Matt, I can't help feeling that this phenomenon is caused by multiple factors, one example I can think of is barrel harmonics and pellet speed. It seems that the more perfectly you can balance all the relevant factors the further you can accurately shoot them. Thanks for your hard work Matt really enjoyed watching.

This is why we have smooth twist barrel. Very very interesting. Thanks.

Absolutely fascinating. Make more PLEASE

Great video bro! Packed with tons of knowledge.

Thanks for such a comprehensive explanation.

Just a stupid thought: why not give the skirt of a pellet a certain twist, something like an aileron on a wing, to give it a certain amount of spin? By adding more 'aileron' you can make the spin faster and vice versa. If that works you might be able to make pellets to shoot a certain distance or at a certain speed. You mentioned the same about the wings on an arrow. Might help stabilize pellets.

wow, thanks for sharing such valuable Infos!!! you saved me a ton of time and money...now i know what to go for to get the desired accuracy

Thanks Matt Very interesting. Took my FXMK2 out yesterday to give your theory a try. Your info helped a lot . Also a clean barrel makes a big difference!

Supremely awesome videos and explanations. Thank You very much for Your work!

Has to be said…………, an awesome video 👏👏👏👏

Excellent video Matt and very well explained. Thanks

Interesting stuff Matt. It’s cool that we now have the ability to really observe and experiment with these things because of the advancement in technology available to all of us. Regarding firearm twist rates, the one downside in high powered rifles is centrifugal force causing bullets to explode in flight. Not a problem with air guns.

Fantastic information in this series!! Thank you

Thanks Matt! Will need to watch this a couple of times! The FX Hybrids shoot very well from my Impact but are way overpriced relative to the competition - will try the JSB KOs when they become available in Canada.

Excellent job, exactly the info I wanted to learn about. Thank you sir.

Some interesting information on this video. With firearms the length of the projectile compared to the weight of the projectile seemed to require different twist rates. While playing with different loads and heads in a .223 rifle I was having some great results with 69 grain rounds. However when trying to shoot a 68 grain round which was longer the twist rate which was 1 in 9 would not provide it with enough stability, rounds were keyholing. 1 in 8 barrel fine rounds flying fairly true still not great. Tighter twist rate again and bang on the money. The difference in accuracy was incredible. Half inch group at 100m with the 69 grain , lucky to get half of them on a 12" inch square target with the longer 68 grain. Look forward to watching your other videos.

Matt, good information! Nice work and video!

Ballistics and trajectory is a fascinating subject never had that problem personally but know a few that have and almost all have corrected themselves once tuned down one thing noticed was rate of spin down range most pellets being of a shuttlecock design making things worse as pellet speed and rotation slow.... it's a subject and a half nice video👍👍👍👍

As always a great video, I always learn something new from you. Hope all is well is SA!

Very interesting Matt. It really explains alot on shooting pellets and slugs at higher speeds, versus lower speed and the BC of the projectile! Got alot out of this video! Watch your 6, and God Bless

Thank you for your research and sharing it

Very insteresting video, like all the ballistic videos serie! I've just purchased some slugs this week for testing and i hope that it will be a improvement in accuracy to long range if i can get them fast enought and if my barrel like them lol thanks you for sharing your knowledge with us!

Hooray for slugs! Thanks for these vids Matt, they're super interesting.

Very good information. Thank you!

thanks for the input I just figured this all out my self a few days ago . Roy

Very interesting! It was nice to see the same thoughtful process in air rifle shooting! I have been shooting long range rifle for years and have become very familiar with most of the physics related in this video. Like yourself, I have had the opportunity to have discussions with Brian Litz about ballistics. Man is he sharp!!! One aspect I have pondered is from my background as a millwright. I occasionally work with turbines, and issues related with high speed rotation. Any item spun on its axis will tend to stabilize, until it reaches its natural frequency, or structural design limitations. If the pellet skirt isn't "perfectly" uniform throughout its geometry, as the rate of twist and velocity increases, the material distribution variance will increase the force of the mechanical leverage on the center of gravity (proportionate to the mass of skirt's inconsistent skirt thickness/ uniformity AND position of this misplaced material relative to the canter of gravity.). The further that mass is from the center of gravity (both axially and radially), the worse the potential of effect. If I understand air pellet dynamics correctly, the skirt slightly flares during the firing sequence to seal the expanding gas, and if there are thin spots on a skirt, they will change/redistribute material more than the thick areas of the skirt. This can effect how the material weight distribution of the skirt maintains or disrupts gyroscopic balance in flight. And if the skirt leaves the crown on one spot on the gas seal it can further create an issue. You mentioned that as well. I agree with you that the pellet design has it limitations. This is so much fun playing with this stuff! So much to learn and so little time to play with it!

Good video. Thanks for sharing your observations and knowledge on this issue. This is an issue that we air-gunners all face at some point in time. Overall good lesson. However, there are many air-gunners who like myself can not afford an FX air rifle with slug liner to get the results that you do. The rifle itself makes a difference in how it performs.

very informative video. Thanks to Matt

An excellent Layman’s explanation 👍

Awsome explanation Matt 👌. Thanks for the info 👍

Very interesting, when I started flying model aircraft I was told (and saw for myself) that any aerodynamic faw is exaggerated as speed increases.

Very interesting matt and well explained 👍 maybe one day someone might try a smooth barrel and a pellet with the spiral on it. Maybe the rifling grooves from the barrel could have a effect on the pellets. Food for thought

I enjoyed the information very much . There are not enough videos on troubleshooting pellet guns and projectiles.

Very cool information! Should help my pellet choices based on the use and platform. Thank you!

This wobble or pitching seems very similar to an archers arrow doing a similar thing i think it's called "archers paradox"where the arrow has to travel over a certain distance with a pitch/wobble but then eventually corrects itself maybe the problem is related to too light or heavy pellets along with the shape of the pellet i think an arrow has to have the correct spine (stiffness)to suit that particular power of the bow etc.maybe it also influences air rifle pellets along with rifle rifling pellet shape/wind deflections too much ft lbs I think it's a very fine balance to master,just a thought,most enjoyable video and very informative,thank you.

just wondered if having a slight point from the middle of the skirt would create a better stabalisation in the deflection of the air like a h and n terminator front on the back .realy enjoyed vid thanks

Thanks for the no sales pitch info very refreshing, in todays airgun youtube vids

Good work

Great video, and thanks for the work and effort you put into figuring things out for airgunners. I seem to have a problem with slugs through choked barrels, I know, a completely different topic, but in my choked barrel the slugs are stable at slower speeds and completely inaccurate and unstable at higher speeds, I don't know why, pellets are cheaper so I shoot more of them and there are more to do tests, or I should say, much more cost effective to do testing with.

In a previous episode you discussed barrels and rifling. Also, photos were shown of pellets that had been shot and the Rifling Mark's were shown. Has anyone investigated the impact to pellets flight because of the Marks made on a pellet from Rifling? Perhaps this could be the source of may anomalies in pellet flight. As mentioned in other videos Diablo pellets were designed to be shot from Smooth Barrels.

Matt thanks for the informative and great, technical content you share here on your channel, like many others, I have been following your airgun videos for sometime now, enjoying and benefiting from your research and knowledge, I am situated in Botswana, where we are fortunate to not have any airgun restrictions or limitations at present, therefore as the importer of Daystate PCP airguns, we have quite a few in .22 .25 and .303 cal and would greatly appreciate your advice on running these airguns on slugs, As you have clearly indicated these types of airguns on max energy do not perform accurately with conventional Diablo type pellets, perhaps you can advise me how to go about getting started using slugs .

Thanks for the info👍👍👍

I learned a lot from this series. Thanks

Thanks for the great information Matt.

He also mentioned FOC front of center which in arrow flight is actually hugely important in target and especially hunting. The higher the FOC, the more down range momentum. I fast light pellet has a very low FOC with very low momentum which in pellet or slug hunting has low penetration. You’re better off with a heavy pellet or slug traveling slower with high momentum which creates high kill possibilities.

Matt, I don't know if anyone has mentioned this before, but you should contact Destin Sandlin of 'Smarter Every Day'. His passion is ballistics and high speed photography. I'm sure he can bring some interesting insight to this question. His friend Mark Rober, also a scientist, can chime in as well. It would be great if you guys could end up collaborating on the subject and get the fun scientist's POV of things.

I know that this is one of your older videos Matt, however this video helps explain what I am experiencing with my .35 cal FX Impact MKii when shooting JSB Diablo pellets at distances further than 70m (860fps). With the .35 cal JSB diablo pellet (81g) the destabilization is pretty severe at 100m. Unfortunately I could only find H&N grizzly slugs for the .35 and they haven’t arrived yet. On my FX impact X .25 cal, at 100m, using Nielsen hollow points slugs, the rifle is a dead accurate laser. For a while I thought my Impact mkii .35 cal was simply highly inaccurate at long range. With this information in your video I am hypothesizing that I see better accuracy at long range with slugs.

Brilliant. Good talk.

Great video. My best guess is that the skirt's drag stabilizing effect falls off too quickly at distance for lighter pellets.