Accurize your Rifle: Barrel Harmonics

Make any rifle into a great shooter! I explain the basics principles of Barrel Harmonics and then offer 3 different approaches to make any rifle shoot great.

[@pewpewnando]

your explanation of the concept is resonably acurate, exept, when its best for the bullet to leave the barrel And i will be making my own video soon explaining this for my channel the barrel is moving the least at the very top and at the very bottom of the sine wave 90 & 270 degrees Where the sine wave crosses the zero line, is where the rate of change is at its highest, and hence the highest rate of barrel movement Hope i have explained it properly have a nice day 😁😁😁

[@CharlesRTinsley]

Thank you, This is the first time I have seen barrel harmonics address, most will just glass bed the action and free float the barrel. I learned about barrel harmonics from a friend when I was 15, he was in his early 30 and married, they lived just down the block from us and he flew control like model airplanes as did I.. That is how we initially met. Later in life learned his uncle was my gunsmith from 1975 until he died, now I know where Joe got his gun expertise. Joe was old school wood worker all hand tools, 2 power tools a drill and 7.25 skill saw. I watched him spend 5 hours hand fitting a Custom built .270 with a feathered walnut stock, Joe hand cut the stock from a slab. he was a true artist and perfectionist Thank you my friend Joe, for having the patience to teach a 15 year old how to properly build, and fit a custom rifle, RIP we will shoot again someday. He would assemble the action minus the stock, and clamp the action and barrel in heavy vice mounted on 6 in reinforced concrete and place a small block chevy cylinder ring over the barrel, he would then proceed to pound the action above the recoil lug with a rubber mallet, the ring will move up and down the barrel, until it finally stops on center node. he would mark the 1/4 wide area of the node glass bed the action, let it cure and clean up any places needed, smoke the barrel, put in stock and look for soot transfer, remove high spots fill and level all of the bedded area and place a credit card at the bottom of the bedding lug after the glass had cured, mark the stock for a bedding rail on the center nod. glass bed the 1/4 inch wide node area with clay used for a dam to keep the glass in a rail 90 degrees to the center bore of the barrel, let it cure then disassemble remove the credit card spacers, clean and finish assembling go sight in at 100 to 200 meters here in MS., his rifles consistently were a ragged hole for a five shot string hot or cold at 200 meters.

[@fezorino]

I like the guitar string comparison. I think this is one of the best explanations I've heard about harmonics! thanks Nathan.

[@Johnnyvoltmax]

Man.. this is a very great explanation!!! Thanks so much for taking time out of your schedule to help the rest of us

[@duxrusso]

Thank you for taking the time for making this video, it has always been in the back of my mind, thank you for bringing it to the light. Best regards! I'm a subscriber! Lol

[@markgunter8847]

Wasn't planning on watching the entire video. However, I'm glad I did...

[@matthewsavageau3650]

Think about this a second. If you can get a bullet to exit the barrel at the same exact moment, every time, it does not matter what part of the wave the muzzle is on. This is impossible though. Where you are saying the the bullet should exit the barrel is when it's muzzle is dead center. This is actually where the muzzle is changing position the fastest and has the fastest up and down speed. So any inconsistencies, in your load, will be amplified when the muzzle is dead center, because the muzzle will be able to move in less time between when bullets exit the barrel. If the timing of the bullet exiting the barrel is off, the muzzle/ barrel angle will have shifted your impact more. The barrel does not stop and wait for the next wave at dead center. The longest "lingering time" is at the top or bottom of the wave. I have found, consistently, my loads perform best at the peaks and valleys. At the top and bottom of the wave is where the muzzle is changing opposite direction. This is where the muzzle lingers longer. This is where inconsistencies in the load can be minimized because if your bullets exit at slightly different times, the muzzle will have shifted position less. The figure 8 shape, the muzzle draws, is typically an accurate description, but not always. you should load for the top and bottom of the 8. The 8 may not be aligned vertically(though typically it is). It could be aligned diagonal or even horizontal. I find my accurate loads quickly. I load a single rounds in charges going up 1/2 grains at a time. This many times will result in 10-15 rounds, all loaded with different charges. I then shoot them all at the same bullseye, at 100 or 200 yards. 200 yards is better. I almost always get two separate groups with scattered shots between them. Those scattered shots are when the muzzle is closer to the center of the 8 pattern. The two congregating groups are when the muzzle is at the top and bottom of the 8 pattern (peaks & valleys). Any of the charges that placed the shot, in groups next to other charges, is where I start my tuning of loads. If I don't like the velocity of an accurate charge, I up it until it groups the next charge in the same area. Then I have hit my second accuracy node. You can do this until pressure signs stop you from obtaining the next accuracy node. Thus obtaining the best accuracy with the best possible velocity. This works for me and my load development time and supplies has dramatically decreased. If I can't find accuracy or nodes, I switch to a different powder or bullet, and eventually gun.

[@dandexinventor]

This is long, but it has a point. Why do we shoot? What about it draws us in? I think it's important to ask ourselves before diving in to become the best of anything, not just shooting. Just out of the Marines and loving rifle shooting, I bought a pre'68 Mouser action Winchester .300 WM with BOSS and mounted a Leopold 10x50. I had to go out to the desert with one box of Federal Supreme BTHP and hope I did need anything else because I was broke, lol. It was the cheapest way I could get into long range shooting at the time. I learned a lot with the BOSS and a bit of experimenting, but only 20 rounds was not enough to get dialed in. My goal was to get sighted in at 100 yards with 3 round groups, then, if I had some rounds left, start tuning the BOSS. By the end of the 20 round allowance, the blast was enormous in noise level and dug a hole at my muzzle like I'd never seen before. My last group was about 1/2 MOA. so I thought I'd achieved my goal and then some. Oh, and I was doing a break-in procedure as well, cleaning between rounds fired. Over the next month or so, I would shoot two more times, two boxes, then three, out further. I noticed the pattern you are talking about, but not changing ammo characteristics, changing the BOSS settings. I read a book (this was 1990) explaining harmonics, but the understanding of what was going on was not as complete as today. All I could do with what I knew is find the best sweet spot of groups and lock it down. It would have been beyond my budget to do anything like reloading equipment. I was ok with what I had going on with a future goal of learning more, doing more. I played around with ideas which were cheap and fun to learn from. I attached tuning forks, rubber strands, changed ammo (which proved to be expensive and improve nothing over what I had) and even tried shooting with the barrel in a trough of water and filming (VHS lol) the wave patterns as I changed the BOSS settings. I already had a bull barrel, so not much changed with those experiments. It was fun though. I settled in with friends who liked messing around the way I did, but one had more money to play with and the other friend had less (just had twins). I ended up giving the friend with new twins, my rifle and buying a new one to start the process over again. The other friend spent a lot of money and the friendly competition was on. We all got to where we could shoot

[@stydras3380]

very interesting, will consider

[@rexlee3710]

I concur. Getting the bullet to exit the barrel as near as possible at the top or bottom of the sine wave is best for accuracy. The barrel vibration slows down and stops at these points before moving in the opposite direction. I shot NRA high power service rifle matches many years using a M1A/M14 NM out to 600 yards with iron sights. Reloaded my own ammo and found the sweet spot for different loads. Great fun and good comradely. The video was good explaining the harmonics of a rifle.

[@KiwiBro8]

Best comment ever :)

[@matthewsavageau3650]

I agree the video is a great video at showing barrel harmonics. Most people don't realize it even exists. It all depends on how interested in precision shooting you are. If 1MOA is great for your amount of curiosity, then that's great. I pursued accuracy when starting, but I frequently found I just couldn't consistently place the bullets exactly where I wanted them when trying for harder smaller targets. When I started achieving 1/2MOA or better, It really solidified what I am able to shoot VS what the rifle is capable of. You reach a point where your skills get better than what many rifle are capable of. Once you know you can shoot touching holes, then it makes you want to spend more time and energy (& $$) tuning a good rifle, optic, optic mount, and ammo. If a newer shooter can have a seasoned shooter give them a known accurate rifle and load, the new shooter can progress in their skills faster because any mistakes are only the shooter. ultimate precision can get you into a rabbit hole, but once you can tune a rifle and load like you can tune a performance motor, it's very satisfying to force the results you were looking for. The Boss system can be great because you can change the tune of the rifle instead of the ammo. Just don't try to tune the boss and the ammo at the same time or you'll never find the right spot. The order of items most affecting accuracy, in my experience is: 1st- The rifle and especially the barrel & equally the shooter and comfortable rest. I trust sand bags more than any bipod for developing loads. 2nd- a scope that doesn't change impact, a 1-piece scope mount, and proper mounting of the scope base and scope to minimize stresses in the optic mounting. 3rd- the bullet 4th- the powder 5th- the brass 6th - can't say primer because when I find the rest of the above mentioned, I don't have a need to mess with different primers. I've never noticed them preventing me from finding an accurate load. For anyone out there trying different bullets, I can tell you I have consistently had good luck, in multiple rifles, with the following bullets: Nosler Accubonds Barnes TSX Sierra Match (most affordable) Sierra Game Kings (most affordable hunting) Bergers (expensive for target bullet, but they are good) If I can't get a rifle to shoot one of the bullets above, I sell it. I have usually not had good luck, for high precision, with Hornady, but that doesn't mean they aren't good bullets. And they have done a tremendous amount to keep the big bore community shooting. I thank them for that. I have not tried any of the newest Hornady bullets like those metal tipped ones yet though. Some of the small bore varmint bullets can get really accurate with Hornady.

[@aldiun16]

Another hidden factor I had no idea about. I'm having flash backs to the archers paradox.

[@aaronunterseher1627]

Litterally what your barrel looks like when you fire a round off

[@AltonRowell-gb1lb]

I got the reloading stuff. Thanks for the video man. You explained it very well. I've been shooting for years,and I really didn't know what was going on. Now that I know, I'm going to fine tune my rifle. I got a icon 30-06 with 3-9 scope. Thanks again.

[@ibanezrg320fm]

I've seen this video probably two years ago and I still reference it. The reason I keep watching it is to see if anyone has posted an actual scientific video and I still can't find one. I play guitar and I've studied guitar and my hypothesis is that there is a comparison to be made but I don't know how to do that which is why I want to see someone smarter than me post a video. The way I see it is on a guitar. If you took a guitar and played an open note, will say E on the bottom string but it doesn't matter which one. We'll say the distance from the nut to the bridge is 25" and we'll just keep it that simple for example sake. The next occurrence of that E note is at the 12th fret which is exactly half the distance of the nut to the bridge. That happens to be 12.5" away from the nut or the bridge. In modern music, there are 11 notes and the 12th note starts the repeat of these notes, ie the octave. I believe a rifle with everything on it; stock, reciever, barrel, scope, brake, everything on it creates a note. The vibration of the cartridge going off is like plucking a guitar string. I wished someone smarter than me could measure this phenomenon because I am 99% sure it is a real thing. Now if you reloaded ammo, you can basically tune the ammo to the rifle and we see that in load development and testing those loads. But something is happening and you are very close to the science of what I'm talking about. I've heard that velocity in relation to bullet weight is one form of creating accurate loads and this can translate to picking another bullet of the same weight as the first and then matching the velocity to continue shooting accurately but I haven't tested it myself. All I'm saying is I wished someone could hook up a rifle to a computer and measure the frequencys coming from the rifle and correlate that to velocity and bullet weight. A tuner is about the closest thing we can use besides ammo tuning to create an accurate rifle

[@bjones9338]

Good experimental method. Your drawing shows the fourth mode of the barrel. The first mode of vibration is likely the most important for the projectile exit direction. Since the barrel is not supported on the free end, the vibrations are similar to a flag-pole, fishing-rod, or an old-time car antenna. My guess is that higher modes of vibration have more to do with interacting with the rifling to affect spin. Good info on the experimental method.

[@Corpsealot]

Hey man! How ya been? Larz here (different account). Glad to see you're still at it! Good video by the way. I tried explaining this same concept to someone once but I was doing a poor job of it.

[@billr4283]

Thank you…a very helpful and informative presentation! Well done!!

[@SOLDTONORM]

Random thoughts...It seems that the only effect that would create a vertical standing wave would be gravity. The spin imparted on the bullet should actually create a helical wave (hold a piece of rope vertically and rotate it). Note that the nodes are still centered in the wave. The suppressor is not a monolithic mass. The mass might be greater at the base, moving the "node" past the end of the barrel but not to the end of the suppressor. While "bull" barrels are more resistant to bending and cancel out some of the vertical wave, the twist of the helical wave is resisted by the barrel mass that is far from the center line by leverage. Watch slow motion of a recoil and you will often see the rifle twist in the shooters hands by recoil from the accelerating bullet mass (greater with greater bullet diameters and masses due to leverage).

[@bookerT_502]

thanks for info, it helps to clean up the rifle from all those static inducing accessories.

[@ronaldkelly191]

Your image is in a 2 dimensions, harmonics is in 3 dimensions. Maybe look at it from the muzzle end, it's moving in a circle. Reduce the circle.

[@dragonflyfab9703]

I like the guitar analogy also. What it brings to light is longer barrels don't vibrate more. They DO vibrate at a lower frequency. To vibrate louder ya gotta pluck harder

[@MyS10Rocks]

Excellent video, I did notice the video is 4 years old as soon as you mentioned the price of ammo and how easy reloading would be, lol. If I could only find some primers, life would be great!

[@ericbovee7680]

Good ideas on how to mitigate barrel whip and how to work with it!! 👍

[@advmotorrad]

thank you so much that great video over this topic

[@fric8489]

Very Good video, but i am pretty sure bullet exit timing window is much larger at peak and valley (end of travel) not at zero axis, so folks are tuning so bullet exits at end of travel when barrel changes direction not when it passes back through zero axis. Timing might be .1-2 millionth of a second for passing through zero axis as that would be very hard to repeat and find versus the larger .5-6 millionth of a second at end of travel since the barrel is decelerating and reaccelerating due to directional change the duration of time bullet is traveling through that event is greater. Respectively, i think you should redraw the bottom graph to show optimal setup/exit timing when barrel is at peak travel. Just my thoughts, i have no detailed calcuations or experience to back this up. In other words the barrel travel distance at end of travel is flatter and stays within a narrower travel distance vs the steep vertical curve at zero axis where it it has greater travel over shorter time. Just my 2 cents again, i have no experience on the matter.

[@garylozowski1419]

An ODS study would be interesting. Operational Deflection Shapes Done by a vibration analyst with the right software might be able to show this and the affect of weights in the barrel or different loads.

[@jorgerodriguez-wv4ul]

Thank u. U really got me thinking

[@dfgiuy22]

Not a bad explanation. My mate and I do professional pest control in Australia and we've found that we get best results going up by .2 grain increments. If .5 works, great but you might be able to tune it even better by doing that. Just a thought. Trying to get accurate .308 through my remington 7600 was a nightmare but found that 168 grain a max, running (I think) 42.2 grains of ar2206h (H4895/IMR4895) out of federal vital shock fire formed brass worked the best. Got a 'couple' of roo's and foxes with it. Gun shoots 1000% better. The only factory rounds that came close (and I tried them all) were hornady super formance. But down here it's about $50.00 a box or $2.50 a bullet. Bit expensive for doing commercial pest control.

[@FUBS0503]

Thank you! I'm studying harmonics this week in school

[@cedrickmcdonald5038]

Man thankyou so much for this information. I had bought a 20inch upper, which its fixed now, but I was having problems with my shot being all over the place just like you explained. I kept trying to tell people that its nothing dealing with me zeroing in my rifle. They just kept on you need to zero in your rifle. So, final I told them, rather if I got to zero in my rifle or not, if I'm standing 25yds back and my shot is going 7inches to the right and I got my back sights center and my front sites level center, then it's no way that I should have been getting a 6 inch grouping being only 25yds back. So, once the guy change out my handguard system it started working and being accurate. You should always be able to at least get 3 moa being that close up, rather if you have to zero in your rifle or not. I figured it had to be some type of vibration going on, for my shot to be flying all over the place like that. Brand new barrel made by Anderson cromv 1 and 9 twist. So, my point of this information is people, please stop thinking everytime a rifle is off the first thing yall holler is o your rifle need zeroing in, o you got to zero your rifle, that's not always the issue.

[@alexb2364]

The top drawing is how it should be, when the rifle is tuned(bullet exits the barrel at either top or bottom of sine wave), the bottom drawing shows where the bullets worst place to exit the muzzle, where he barrel is moving the most. Just to clarify how this works.

[@YoderTexas]

Just looking at your display, I see possibly another way to tune your harmonics. Barrel length. I have seen other vibrating rods, pipes, etc. under a strobe light which makes the sweet spots stand out from the areas that are vibrating. I'm sure this could be done on a rifle, but the vibration we're talking about only lasts a fraction of a second. It would take some serious high speed camera equipment to capture the sweet spots on a video recording.

[@Wedelj]

I have heard of some gunsmiths who would get a cartridge they wanted, a bullet they wanted, and the powder charge to shoot it at the speed they wanted. They would barrel the gun with a long barrel, and shoot a group. If the group wasn't as good as they wanted, they would chop 1/4" off the end and re-shoot. Continue until the group is pretty tight, then start cutting off either 1/8th" or 1/16th" until the group was super small.

[@drd1924]

@@Wedelj very interesting...I like it....one more refinement other than seat depth

[@tsafa]

Great video. I now understand better. Does the barrel need to settle down between shots? If the bullet is coming out consistently at the top or at the bottom of the wave, I understand a different point of impact shift.... but why would that shift not be consistent?

[@O-cDxA]

I read an article making fun of bedding materials like Bondo or silicone caulk. However, the author didn't mention why these materials do not work. Please clue me in on why rubber caulk would not work as a bedding material. I would think allowing the action of the rifle to vibrate freely would be just what you want, but from what I understand now, I'm guessing ideally you want to clamp the receiver down as tightly as possible to something extremely rigid but form fitting so that you cancel out as much vibration in the receiver as possible. Is that the case ? ( with both examples having a fully free floated barrel. ) Why would Bondo or JB Weld not work ? Both create a perfect mould and are rigid. Also, I'd like to ask if when free floating a barrel, where that you start the bedding. Do you bed from the barrel lug on back, or have the barrel lug free floated too ? Great video ! 👍

[@maxwelm7408]

I have two howa. Both in .308 one is 24” Varmint barrel and is free floated with a laminate stock. But the other howa is 22” sporter barrel walnut stock but NOT free floated it got a pressure point at the end. And both shoots clover leaf in 100 yards

[@scottkoresky5879]

No mention of CBTO in relationship to the lands. I have been adjusting factory loads by pulling bullets just past my BCTO and press to specific lengths and have tested yesterday with same hole results at 100.

[@PeakyBlinder]

Interesting stuff

[@davejalenderki]

Is that dowel rod made of oak or pine?

[@SeanPwnery]

Essentially this is also the holy grail of handloaders goals too - to perfect a bullet, powder, and charge formula that achieves this. (edit : oh wait, you got there towards the end!) :p

[@landrenduckett3006]

I have a browning bar with the boss and it is a tack driver.

[@garylozowski1419]

Do you think a 22 long rifle cartridge in a heavy large diameter, rather short 18” barrel, does this ?

[@MrDirtysteve75]

Common problem with synthetic stocks is forend touching a free floating bbl and or bipod on flimsy stock putting pressure on bbl.

[@nicholasgad2781]

I think you might have the diagrams the wrong way around. The top wave would be when it reaches the extreme of a swing (if its side to side).

[@RedShiftedDollar]

At what point does a supersonic round cross the sound barrier?

[@slightenigma]

Suppose you find a harmonic node in a particular caliber with xy.z grains of a powder at a particular grain weight. Will the harmonic node be close with a heavier projectile?

[@tony55752]

No, This is about barrel time and contact surface. Your barrel will like a given bullet at one certain velocity. You can use another compatible powder as long as it is driving the same bullet at the same speed you will get similar results.

[@drd1924]

@@tony55752 any consitent changed, turns into another variable that must be accounted for until consistent again....Agree with UXO Tony....change bullet = a likely change in load is usually called for.

[@matthewsavageau3650]

also, don't underestimate letting your barrel cool and always foul your barrel with 1 to 3 shots before testing for accuracy. When testing for accuracy, I always shoot fouling shots, let the barrel cool, then do my accuracy testing with 2 shots at a time. I let the barrel cool fully, typically 10 minutes, with the rifle resting upright, and the bolt open. The reason I shoot only 2 shots at a time is: the barrel starts to heat up after 2 shots. Most factory barrels have stresses throughout the barrel, from manufacturing it. As the barrel heats, typically it will point in a different direction, from metal expanding more on one side than the other. Shooting, while your barrel is always cool, will bring out the best accuracy. Yes, Its a pain waiting for the barrel to cool, but once you found your accurate load or ammo, you'll be glad you took the time. When hunting, you will almost always be shooting a cold barrel. If your shooting high volume, it's definitely worth looking at getting a thicker match barrel installed. most match barrels are cut rifling, which helps reduce the chances of stored internal stresses. Some are even stress relieved. A thicker barrel also minimizes barrel whip. This will cause more ammo or loads to shoot better in your gun and it won't change point of impact as much when your barrel heats up.

[@aaronunterseher1627]

Pause! You missed one critical aspect about the reloaders method! You use charge wait to determine velocity! Your es/sd is determined by ignition which gives your at range performance! Your SEATING DEPTH tunes harmonics! You have 2 nodes your looking for. Your velocity node (changes from bullet to bullet and powder to powder and primer to primer you can't miss Match anything) which will establish your low es/sd node by doing a charge wait latter test and using a chronograph... You do the latter by .3 grains because nodes are typically found in .2s so with .5s you can pass a node with out noticing it. Then you have a Harmonic node which determines your physical group size as it pertains to the vibration in your barrel. You can correct it by adjusting seating depth or by the use of a barrel tuner... There are thread on tuners which are far far easier to use...

[@ivobiancucci4528]

Weatherby Vanguard has a barrel pressure point at the end of the stock - people trim that to make it free float only to change the harmonics next they buy another stock etc. I think the japenese knew what they are doing

[@maxwelm7408]

I have two howa. Both in .308 one is 24” Varmint barrel and is free floated with a laminate stock. But the other howa is 22” sporter barrel walnut stock but NOT free floated it got a pressure point at the end. And both shoots clover leaf in 100 yards

[@SOLDTONORM]

This assumes that the wave is 2 dimensional while the bullet is being spun by rifling. I suggest that the barrel muzzle is moving in a circle...or possibly a combination of 2d and circular.

[@drd1924]

good point.....it is usually elliptical and not perfectly circular...I do not know why this is tho and it would be great if someone experimented to find out why since the elipse shape will change in its direction from say: 1'Oclock to 2 Oclock etc. So quite possible there is not only 3d vibration patterns being exerted but a 4th....tortional, due to twist maybe. But I am glad you pointed out that a barrel does not just vibrate up and down as if it is held in a single plane like drawn on a piece of paper

[@bigwestreviews4933]

This is where it gets interesting. I’ve personally been trying to approach this problem in engineering classes for years now and haven’t found an exact solution. Ultimately though I think cylindrical coordinates are the best method to guesstimate for the exact reason you mention.

[@jetthreat5000]

Greenhill formula :)

[@philip6419]

If the point is to make a smaller group there's a 4th method.. the ballistic method. Not everyone can do it though. Simple explanation.. One secures the weapon, then fires it and measure the speed of the exiting bullet. [Obtaining this device can be a problem] If you can get it.. then get the book [there is one] that has every bullet in your caliber and see what it states the speed is suppose to be. Then reload it [as Nathan does] to those specs, OR.. look for the brand that matches YOUR weapons expected speed. Get it, and THAT will be your tightest grouping.

[@Americanblood76]

Twist rates is all I worry about.

[@thelocustemperor]

Do bolt rifles experience barrel whip like semi auto rifles?

[@AlessioSangalli]

Why not, the action has no part in this no?

[@fuhq5121]

Yes. Different chassis though so usually easy fix

[@keitha.9788]

Yet another method is to "tune" the barrel using something like the BOSS on old Browning A-Bolt rifles.. (Harrell Barrel Tuner)

[@hosoiarchives4858]

This is wrong. The sine wave is used incorrectly

[@christopherarroyo1734]

Can someone tell me why my gun groups better after the barrel is warm

[@DmitriyLaktyushkin]

Temperature affects the tensile modulus and expands your barrel physically thus changing your barrel's natural frequency.

[@drd1924]

stress is relieved more when warm.....may need to be cryo'ed or freefloated.

[@gssmith1986]

Go to 0:11 on this slow motion guitar string video: kzbin.info/www/bejne/boqqgqCMaLOrg6s Slow the video down to 1/4 speed and watch the nodes on the guitar...they stay in one spot. This is the same for a rifle barrel. By tuning the load, you're trying to change the wavelength (the frequency) of the vibration so a node occurs at the muzzle. This the place that everyone else below is saying is moving fastest, but it's not...it is not moving at all if you get the frequency to generate a wave the right length to line up there. This is the most accurate location. Even if you're off a bit, it is much smaller deviation than aiming for the "stops". Would like to see a slow motion video of a rifle barrel being fired. I've got ruger international with a pencil thin barrel and mannlicher stock, which are notorious for being unaccurate. This thing is dead accurate and tight and I'm convinced that the forecap on the mannlicher stock is holding the muzzle still and forcing the node to that location. And that's shooting cheap Federal 243b's.

[@Americanblood76]

This type of research should be done already by the factory.

[@drd1924]

They did, they don't care and will take your $600 bucks no matter how it shoots.

[@6handicap604]

How can the factory do it? They do not know what you are shooting with. Hornady or Winchester or hand loads? How many grains of what powder, how heavy a bullet, all are different.

[@nj-bz8pv]

God I miss the days off 30 dollar hunting rounds

[@johnkoenig496]

They're called CARTRIDGES, NOT bullets.

[@0x00zero]

Drawing exactly wrong. Top image has bullet leaving at ideal time (slowest). Bottom is worst (fastest)

[@drd1924]

unless it's a harmonic node

[@michaelenochs4033]

I'm not so sure about that. I do alot of guitar recording and those are called transients. That top image is the loudest in a tracks recording which I can relate to this image better from.

[@6handicap604]

@@michaelenochs4033 Look at the drawing, it is basically correct as far as the vibration, the transition is at the top and bottom where the vibration slows then comes to a stop then goes the opposite direction. The best exit point is during that stop. The way he has it drawn the bullet exits during the fastest moving part of the vibration, not the slowest. Put a time line along the vibration, what is your window of time for the bullet to exit as drawn, what is your window of time at the top or bottom to hit that node? As a matter of fact, the node is defined by the transition from one direction to the other.

[@michaelenochs4033]

@@6handicap604 I see what you're saying. Thanks for sharing that!

[@REDNECKROOTS]

Wrong , just let the adults talk. Go outside n play.

[@Cageey1117]

Very over simplified. An AR-15 has a vibrational wave travelling 20,000 fps will cover 32 in. (2X barrel length) in roughly .000133 seconds. Over .003 seconds the wave will oscillate along the barrel 22.5 times. .003 seconds is the time lapse from pressing the trigger till the projectile leaves the muzzle.

[@werdh2ofall]

Very informative and good information. However, it was hard to watch considering everything was referred to as “bullet”. Boxes of bullets, bullet goes down the barrel, bullet goes off etc. Admittedly, I am a little OCD when it comes to language.

[@markroeder2491]

Bad info...this is wrong. You actually want the bullet to exit the barrel as it hits the top or top or bottom of a cycle. You never want the bullet to exit the barrel in the middle. Think about this. The barrel is moving and if you are in the middle of a cycle you must hit the exact point in time of exit in order to hit a particular point of impact. If you are a fraction early or late the shot will be high or low. If you are at the top or bottom of a cycle your point of impact is reduced by half. If you are early at the top of the cycle your point of impact will be low. If you are late, your POI will again be low because the barrel is on the downswing. You've double the timing for an accurate shot or halved the point of impact. Load adjustment is backwards thinking. Keep that a constant for everyone, then tune your barrel for that standard load. The length of barrel and weight at the end of a barrel are key.

[@sean1ni]

Mars Rover is right, TURBINEator is wrong. Mars has 2 up votes and TURBIN has 4, this shows people need more physics education or to pay more attention when they were in a physics class.

[@chrissenator]

Would a silencer restrain som of the barrel harmonics?.

[@SailDallas]

Additionally, the SLOPE of the oscillation will be closest to ZERO (thus less susceptible to to variation) near the top or bottom of the curve. The SLOPE will be greatest at the NODE (point of GREATEST variation over different shots). HOWEVER, as you tune the barrel, you don't really need to know this. You'll simply set your tuning device to give you the most repeatable grouping. Problem solved. Good video. Thanks.

[@longobardir]

The barrel vibrates radially around its entire axis not just up and down, it will draw a circle shaped pattern if the bullet exits the muzzle as it is at its maximum deflection. A properly "tuned" load only has to be of the correct and consistent velocity to ensure the bullet exits the muzzle as the peak vibration wave returns to the chamber. This can be estimated very closely by measuring usable length of the barrel and by using the speed of sound in steel (18,000 fps). So for example, in a 30" barrel(28.575" effective for bullet travel), shockwave traveling at 216,000 in/s the barrel would oscillate 7559 times in 1 sec, or 7.559 oscillations per 1ms. From this you can find one full oscillation (chamber-muzzle-chamber) takes 0.264 ms. A bullet traveling 2425 fps would exit the muzzle after 1.445 ms (1.445/0.264=5.47) this means the wave would not be completely back to the chamber and the bullet would be exiting the muzzle at a high point in it's vibration. by getting this # to be a whole number it ensures the bullet leaves the barrel at the exact point the vibration reaches the chamber. So the velocity of this round needs to be adjusted either up or down (to make 5 or 6 complete oscillations). Pushing that same bullet to a velocity of 2599 fps makes it leave the barrel in 1.313ms (1.313/0.264=4.97) this load would leave the barrel after 4.97 oscillations and would probably be more consistent than the first load. These measurements will get you very close to the velocity target you need to hit for your rifle but there are subtle differences in each rifle (barrel steel, thickness, etc) that will not make this 100% accurate. 2599fps wont be the exact sweet spot for every 30" rifle shooting a 0.264 140gr projectile, but it'll be a much closer start and will save you on ammo. A range of 2580 to 2620 would probably contain the sweet spot you're after and narrows the target velocity window down by a lot, from there use your chronograph to tell the true story.

[@longobardir]

the slope of the vibration wave would be greater but the actual steel of the barrel will be at it's neutral point. Yes the wave is rapidly transitioning from positive to negative (or east to west) but if the bullet leaves the barrel at a node then the actual barrel itself is at rest since the waveform momentarily hits zero as it crosses it.