Can muzzle brakes reduce or increase ES/SD?

[markl323]

Can muzzle brakes cause high ES/SD? From time to time I see forums comments saying that they can.
Have you ever observed this personally? For those that have to shoot with brakes, it would be useful to know which brands to avoid.

Then Eric Cortina said in one of his videos that his EC tuner brake diverts gas in a way that will reduce ES/SD. What are your thoughts? Has anyone been able to confirm this via testing?

 

[EXSOCAL]

Thinking about it logically, the bullet gets all its speed inside the barrel. The moment it leaves the barrel and enters the atmosphere, that is it and normal physics apply. Unless you are physically contacting the bullet or shooting into some sort of vaccuum or alternate atmospheric condition similar to what happens inside a suppressor, the speed will not change, thus, the ES/SD will not change. I go back and forth between bare muzzle, a 5-port Salmon River Solutions brake, and a TBAC Dominus all the time. Bare muzzle and brake, there is no difference. Bare muzzle / brake and suppressor, there is less than a 1% difference.

 

[straightshooter1]

Can muzzle brakes cause high ES/SD? From time to time I see forums comments saying that they can.
Have you ever observed this personally? For those that have to shoot with brakes, it would be useful to know which brands to avoid.

Then Eric Cortina said in one of his videos that his EC tuner brake diverts gas in a way that will reduce ES/SD. What are your thoughts? Has anyone been able to confirm this via testing?

Let's be clear that the video you posted mentions nothing about ES/SD's. . . only that his tuner-break with reduce group size. We're not just talking about a break. When we're talking about ES's and SD's, that usually has to do with velocities. Though a group's ES involves group size. You didn't specify which.

I do use Cortina's tuner-break (like the on in the video pic you posted) on my 6.5 PRC and yes, it has reduced my group sizes. A break alone will change a POI, but they are not a "tuner". Tuning is about getting the timing for the bullet's barrel time in sync with the harmonics of the barrel where the bullet is being released at a time in the vibration that has the least movement. If velocities could be exactly the same, which they never are (except rarely where 2 or 3 in a row are by chance), you can have one small hole when the bullet is released that the very same time in the harmonic vibration. In the pic below, I was playing with the tuner setting starting at 6.5 and moving it down to 4.0. I like the setting from 5.0 to 4.0 and find I can keep the groups touching in that range making small adjustment according to ambient temperature changes. The setting at 6 and above just never gives me the smaller groups . . . having tested this more than once.

Diverting the gases may help in some small way, but that can't be tested unless one uses the same tuner with only the difference in the way the gases are diverted. The gases that Cortina refers to escaping before the bullet, is mostly blowby gasses that start down the barrel before the bullet is fully engraved and is of a low mass having little effect, if any, on the bullet. The tuner itself is the thing that can really produce any change. . . not that gas.

Keep in mind that any time something is attached to the barrel, that alone changes the harmonic vibration and will effect POI. Breaks of different weights, shapes and sizes will effect that differently and in some cases may act a little bit like a tuner making for a somewhat smaller group . . .or even larger. Which break on a particular barrel will do that, no one can say any more that one can say a particular setting on a tuner works for the particular barrel. It's would have to be trial and error test of breaks to see which might do that.

There has been extensive testing by many, many shooters using various tuner's and tuner-breaks and they all work. I've used 4 different ones that all have worked, but some seem easier to use and get a result than others.

Here's that target from my 6.5 PRC I did back in May:

 

[ballisticdaddy]

If you read it on the interweb then it must be true! Tuners will change barrel harmonics but not velocity and yes I have tested it.

 

[markl323]

Let's be clear that the video you posted mentions nothing about ES/SD's. . . only that his tuner-break with reduce group size. We're not just talking about a break. When we're talking about ES's and SD's, that usually has to do with velocities. Though a group's ES involves group size. You didn't specify which.

I do use Cortina's tuner-break (like the on in the video pic you posted) on my 6.5 PRC and yes, it has reduced my group sizes. A break alone will change a POI, but they are not a "tuner". Tuning is about getting the timing for the bullet's barrel time in sync with the harmonics of the barrel where the bullet is being released at a time in the vibration that has the least movement. If velocities could be exactly the same, which they never are (except rarely where 2 or 3 in a row are by chance), you can have one small hole when the bullet is released that the very same time in the harmonic vibration. In the pic below, I was playing with the tuner setting starting at 6.5 and moving it down to 4.0. I like the setting from 5.0 to 4.0 and find I can keep the groups touching in that range making small adjustment according to ambient temperature changes. The setting at 6 and above just never gives me the smaller groups . . . having tested this more than once.

Diverting the gases may help in some small way, but that can't be tested unless one uses the same tuner with only the difference in the way the gases are diverted. The gases that Cortina refers to escaping before the bullet, is mostly blowby gasses that start down the barrel before the bullet is fully engraved and is of a low mass having little effect, if any, on the bullet. The tuner itself is the thing that can really produce any change. . . not that gas.

Keep in mind that any time something is attached to the barrel, that alone changes the harmonic vibration and will effect POI. Breaks of different weights, shapes and sizes will effect that differently and in some cases may act a little bit like a tuner making for a somewhat smaller group . . .or even larger. Which break on a particular barrel will do that, no one can say any more that one can say a particular setting on a tuner works for the particular barrel. It's would have to be trial and error test of breaks to see which might do that.

There has been extensive testing by many, many shooters using various tuner's and tuner-breaks and they all work. I've used 4 different ones that all have worked, but some seem easier to use and get a result than others.

Here's that target from my 6.5 PRC I did back in May:
View attachment 8484081

I have the PRS version on the way. I believe it can change group size. Whether it can reduce group size further after seating depth tests, that remains to be seen! But even if it doesn't, it is still a handy tool when there is a change in elevation, weather, etc.

 

[markl323]

If you read it on the interweb then it must be true! Tuners will change barrel harmonics but not velocity and yes I have tested it.

I am not saying the claim is true.

 

[tinker]

I have one barrel with a tuner, It made no difference in Velocity but does make a difference in group size.

Interestingly That Litz guy made a post on facebook a week or so ago saying that there is no barrel movement before the bullet leaves the barrel and that means no such thing as harmonics which would also mean barrel tuners don't do anything.

It should also be said that he is also one those guys who says "small sample sizes don't mean anything".....yet his video he posted was
ONE shot......

 

[markl323]

that's interesting. Brian Litz had given some very good tips such as trying different types of primers and I was able to confirm that.

although I don't agree with some of the things he's said. one is that seating depths do not make much of difference on Berber Hybrid bullets. not in my testing, a 0.003 jump can shrink or expand a group by half an MOA. this was with the Berger Hybrid Target 140 gr.

regarding tuner, mine arrived but I haven't had a chance to try. although I think they likely work. question is how well? (I have not seen a conclusive video, even from Eric Cortina himself).

We know that Tac Ops can tune their barrels to a specific ammo (Federals), probably by applying the pressure to the barrel somehow, and get 1/8 - 1/4 MOA accuracy.

On Litz's video:
- best way to shoot for groups is still free-coil then.
- he did not say how thick or how long that barrel is. if the barrel is thick and short, it will probably flex less.
- a tiny bit of invisible harmonics will probably matter at 100 yards because the longer the distance the error gets magnified.
- how would adjusting seating depths work then?
- my conclusion is that there's invisible harmonic vibrations in the video but it's too small for the naked eyes. but you will see the effects at 100 yards.

I have one barrel with a tuner, It made no difference in Velocity but does make a difference in group size.

Interestingly That Litz guy made a post on facebook a week or so ago saying that there is no barrel movement before the bullet leaves the barrel and that means no such thing as harmonics which would also mean barrel tuners don't do anything.

It should also be said that he is also one those guys who says "small sample sizes don't mean anything".....yet his video he posted was
ONE shot......

 

[kthomas]

I have one barrel with a tuner, It made no difference in Velocity but does make a difference in group size.

Interestingly That Litz guy made a post on facebook a week or so ago saying that there is no barrel movement before the bullet leaves the barrel and that means no such thing as harmonics which would also mean barrel tuners don't do anything.

It should also be said that he is also one those guys who says "small sample sizes don't mean anything".....yet his video he posted was
ONE shot......

I've yet to see a slow motion video that was able to capture any evidence of the "barrel whip" phenomena. Even in .338LM barrels.

To the sample size thing - why would a barrel move on one shot but behave differently on another shot? I don't think barrel harmonics only exists on some shots but not others. It's either there or it isn't.

 

[Yondering]

Short answer to the OP: No, a muzzle brake does not affect consistency of the bullet's velocity (ES/SD). But what a brake can do is affect velocity readings over an optical chronograph; pressure waves can affect readings if you're a little too close, and muzzle brakes do affect those pressure waves.

So if someone is claiming to have "proof" that a brake made their velocity readings more or less consistent, most likely the difference they're seeing is in the accuracy of the measurement, and not the true velocity of the bullet itself.

 

[Doom]

...Interestingly That Litz guy made a post on facebook a week or so ago saying that there is no barrel movement before the bullet leaves the barrel and that means no such thing as harmonics which would also mean barrel tuners don't do anything….

Care to share where he made that statement?

 

[kthomas]

Care to share where he made that statement?

I haven't seen that exact statement, but if you have FB, Applied Ballistics has uploaded a few slow motion videos of the end of the barrel as the projectile exits.

There's no discernable "barrel whip" visible, at least from what I can see.

It would be interesting to do an experiment where the rifle is in a fixed fixture, with sensors placed across the length of barrel to capture any movement as the bullet progresses through the length of the barrel. Should be relatively simple to do (in theory), the sensors would just have to be sensitive enough to capture minute movements, and to be able to capture multiple data points in a very short duration of time.

There's probably multiple ways in which such an experiment could be conducted.

 

[tinker]

I haven't seen that exact statement, but if you have FB, Applied Ballistics has uploaded a few slow motion videos of the end of the barrel as the projectile exits.

There's no discernable "barrel whip" visible, at least from what I can see.

It would be interesting to do an experiment where the rifle is in a fixed fixture, with sensors placed across the length of barrel to capture any movement as the bullet progresses through the length of the barrel. Should be relatively simple to do (in theory), the sensors would just have to be sensitive enough to capture minute movements, and to be able to capture multiple data points in a very short duration of time.

There's probably multiple ways in which such an experiment could be conducted.

Yes that was the facebook post I was talking about.

In his comments he claims there is NO movement and it is shouldered. I believe one can have an instance of no detectable movement.......but one video is a pretty small sample size. LOL

I have actually been looking into high speed cameras to play with and it would be fun to try to capture some of that. It's more pricey that I want to spend even for a used one right now for just something to play with. But I am still looking into ideas.

 

[tinker]

that's interesting. Brian Litz had given some very good tips such as trying different types of primers and I was able to confirm that.

although I don't agree with some of the things he's said. one is that seating depths do not make much of difference on Berber Hybrid bullets. not in my testing, a 0.003 jump can shrink or expand a group by half an MOA. this was with the Berger Hybrid Target 140 gr.

regarding tuner, mine arrived but I haven't had a chance to try. although I think they likely work. question is how well? (I have not seen a conclusive video, even from Eric Cortina himself).

We know that Tac Ops can tune their barrels to a specific ammo (Federals), probably by applying the pressure to the barrel somehow, and get 1/8 - 1/4 MOA accuracy.

On Litz's video:
- best way to shoot for groups is still free-coil then.
- he did not say how thick or how long that barrel is. if the barrel is thick and short, it will probably flex less.
- a tiny bit of invisible harmonics will probably matter at 100 yards because the longer the distance the error gets magnified.
- how would adjusting seating depths work then?
- my conclusion is that there's invisible harmonic vibrations in the video but it's too small for the naked eyes. but you will see the effects at 100 yards.

When you try the tuner, if your barrel has similar results to mine (they all could vary) you should see a CLEAR trend happening.

I did a video on it and you can actually see the size of the groups change from setting to setting. Of course the "3 shot groups mean nothing" crowd will say it means nothing. But that is not the case when you can see a very clear trend.

 

[Slides]

I've yet to see a slow motion video that was able to capture any evidence of the "barrel whip" phenomena. Even in .338LM barrels.

To the sample size thing - why would a barrel move on one shot but behave differently on another shot? I don't think barrel harmonics only exists on some shots but not others. It's either there or it isn't.

Are you going to be able to see 0.005" in a video? That's your 0.5MOA offset/sweep at 100 yards. You are talking movement that even the partial pixel motion amplification camera/software systems used in industrial vibration/fault analysis would struggle to pick up without very tight framing. If Bryan Litz was serious about it he would hire someone for a day to frame up real close to a muzzle with their rig or get a really tight, really high speed footage package processed by a motion amplification mob.

Unless you are using lazer interferometers, or ultra tight break beam arrangements you aren't going to identify movement clearly and consistently at the scale that matters.

 

[Emerson0311]

I am inclined to believe what Litz says, vs a random private person doing groups at the range. No one is infallible of course, but the public face of his business, his education, and experience back up his conclusions rather well. I find the public professional ballistic conversations usually make broad conclusions that apply to the end result, and private individuals usually focus on one facet, or one narrow part of the process. I’m also mistrusting of someone using their skills to sell a device. Erik Cortina being an incredible shooter may not all be causally related to his tuner.

 

[brianf]

Please God …not another tuner thread

 

[chevy_man]

I am inclined to believe what Litz says, vs a random private person doing groups at the range. No one is infallible of course, but the public face of his business, his education, and experience back up his conclusions rather well. I find the public professional ballistic conversations usually make broad conclusions that apply to the end result, and private individuals usually focus on one facet, or one narrow part of the process. I’m also mistrusting of someone using their skills to sell a device. Erik Cortina being an incredible shooter may not all be causally related to his tuner.

Litz likes to talk in absolutes when it suits him, but won't respond to critical thinking other than to say "you're wrong".

He certainly knows his ballistics.

He's not the end all of exterior factors on ballistics.

 

[kthomas]

Please God …not another tuner thread

 

[Slides]

I am inclined to believe what Litz says, vs a random private person doing groups at the range. No one is infallible of course, but the public face of his business, his education, and experience back up his conclusions rather well. I find the public professional ballistic conversations usually make broad conclusions that apply to the end result, and private individuals usually focus on one facet, or one narrow part of the process. I’m also mistrusting of someone using their skills to sell a device. Erik Cortina being an incredible shooter may not all be causally related to his tuner.

Has nothing to do with tuners necessarily (they just shift the impulse response time if you want to), applies equally to tuning loads for muzzle exit time on a bare barrel as many F class/benchrest shooters aim for with no muzzle attachments to minimise vertical dispersion.

Didn't one of these mobs do an hour long interview with a guy whose entire career was based on doing simulations from light arms to artillery for US "defence" with a package that absolutely delivered axial and horizontal impulse response?

Again, given the resources available to him, if Litz wanted to PROVE his position he could use accelerometers, laser interferometers or combinations of varying techniques to clearly define barrel motion before bullet exit. He chooses not to.

 

[JerkyFreak]

There was a guy working for Border barrels that attached a device to the fron of a .22 rilfe clamped to a bench. He used it to record the angle of the muzzle at bullet exit. This correlated exactly with the recorded group dispersion. He then placed a weight to alter the movement and muzzle angle and showed how the group shrunk.

Using barrel vibrations to tune a barrel

 

[LRShooter101]

Care to share where he made that statement?

Sorry, but if no one can post the actual source from Litz, then I am calling BS!

Having been to numerous AB/Litz training events, he discusses the impact of harmonics/whip.

 

[brianf]

We all know you’ll be sucked in with 5-8 posts.

 

[brianf]

To keep this thread from becoming a total shit show as usual.

Can we all agree that it will be a rimfire discussion or a center fire discussion

They are very different and when crossing paths it get even more ridiculous

Just a suggestion

 

[JerkyFreak]

To keep this thread from becoming a total shit show as usual.

Can we all agree that it will be a rimfire discussion or a center fire discussion

They are very different and when crossing paths it get even more ridiculous

Just a suggestion

Not sure what you are on about. Narrel weights, tuners, barrel harmonics etc all work the same regardless of rimfire or centre fire.

 

[brianf]

Not sure what you are on about. Narrel weights, tuners, barrel harmonics etc all work the same regardless of rimfire or centre fire.

the old “they are the same”

But you can’t play with seating depth with center fire, and many think seating depth is part of the vibration equation.

So if one variable is the tuner in rimfire but seating depth and tuners are 2 variables in center fire…they are not the same when speaking about conclusions and theories. …that not scientific on its face.

It’s another variable in the long list of unknown and unrecorded variables which is why there is no consensus on what or how they work.

If tuners were easy to discuss there would be a mathematical formula which all follow, but there isn’t. Some tuner people have some basic formulas but they all differ.

Not saying if they work or not but anyone with a scientific background shoots holes in that immediately

 

[tinker]

the old “they are the same”

But you can’t play with seating depth with center fire, and many think seating depth is part of the vibration equation.

So if one variable is the tuner in rimfire but seating depth and tuners are 2 variables in center fire…they are not the same when speaking about conclusions and theories. …that not scientific on its face.

It’s another variable in the long list of unknown and unrecorded variables which is why there is no consensus on what or how they work.

If tuners were easy to discuss there would be a mathematical formula which all follow, but there isn’t. Some tuner people have some basic formulas but they all differ.

Not saying if they work or not but anyone with a scientific background shoots holes in that immediately

Kind of sounds like you didn't read the article that Jerkyfreak was kind enough to post. It clearly shows a LOT of what is going on.

it's not ALL spooky voodoo.....

 

[markl323]

Sorry, but if no one can post the actual source from Litz, then I am calling BS!

Having been to numerous AB/Litz training events, he discusses the impact of harmonics/whip.

this is his post https://www.facebook.com/BryanLitzBallistics

The Phantom Camera motion tracking feature allows us to measure how much the muzzle moves prior to bullet exit. In this case, the muzzle moves about 0.057" rearward during the time the bullet is moving down the barrel.
This is a Remington 700 BDL in 30-06 firing 180 grain bullets.
Many shooters talk about barrel harmonics and nodes. Watch carefully, there is no visible movement of the barrel in the vertical direction.
First order dispersion effects are going to be driven more by variations of the VISIBLE movement, rather than the INVISIBLE harmonics.
Experienced shooters understand the importance of consistently applied grip, cheek, shoulder and other pressures on the rifle as well as good trigger control and follow thru. These fundamentals aim to make the barrel movement as consistent as possible during recoil/barrel time. In other words, the very fundamentals of marksmanship are based on the sensitivity of precision to the recoil movement during barrel time. Harmonics or not, THIS is the meat and potatoes of dispersion mechanics; no suprise, it's the most VISIBLE part!
Follow me for more evidenced based ballistic analysis

 

[Slides]

the old “they are the same”

But you can’t play with seating depth with center fire, and many think seating depth is part of the vibration equation.

So if one variable is the tuner in rimfire but seating depth and tuners are 2 variables in center fire…they are not the same when speaking about conclusions and theories. …that not scientific on its face.

It’s another variable in the long list of unknown and unrecorded variables which is why there is no consensus on what or how they work.

If tuners were easy to discuss there would be a mathematical formula which all follow, but there isn’t. Some tuner people have some basic formulas but they all differ.

Not saying if they work or not but anyone with a scientific background shoots holes in that immediately

You understand people do this all the time when characterising measurement testing setups/equipment? You fix other variables or measure the sensitivity of the output to their variance and either fix or control or compensate for them or add the variance produced from the range of conditions during testing to your uncertainty calculation. You don't just throw your hands in the air and say it's unknowable but Litz is correct by magic.


It's almost like he should consult actual trained metrologists when doing this stuff.

 

[JerkyFreak]

this is his post https://www.facebook.com/BryanLitzBallistics

That's great. /S

To measure is to know. I don't see any measuring going on.

I am detecting a slight downward movement at the muzzle, but that could just be an artifact of viewing on a cellphone.

What doctor Kolbe observed was not an up/down movement , but an angle change at the muzzle. Which makes more sense than seeing the muzzle flapping around.

 

[Yondering]

this is his post https://www.facebook.com/BryanLitzBallistics

I'll preface this by saying I use those Phantom high speed cameras at work too.

Perspective is important here. Think about the largest amount of vertical POI change you might see on target at 100 yd due to harmonics (whether that's from different seating depth, powder charge, etc doesn't really matter). With most decent rifle barrels, even 2" change would be pretty large - but now think about how tiny the movement at the muzzle has to be to account for 2" at 100 yards. We're talking about 1/30th of one degree; you'd need very precise indicators against a finely graduated background to be able to detect that with one of these high speed cameras.

Some of you are talking about not seeing any harmonics in high speed video, as if you're expecting to see some visible whip. It's not going to move around like an actual whip; we're talking about movement so tiny as to be imperceptible, but that doesn't mean it's not there. The .057" of rearward movement mentioned by Litz is massive in comparison to the miniscule vertical movement of barrel oscillations.

Most of us aren't qualified to disagree with Litz with any real authority on a lot of what he talks about, but in this particular instance I am qualified, and wholeheartedly disagree with his assertion that not seeing harmonics in his cameras indicates it isn't there. It's far more likely he wasn't set up correctly to detect it, much less measure it.

 

[tinker]

I'll preface this by saying I use those Phantom high speed cameras at work too.

Perspective is important here. Think about the largest amount of vertical POI change you might see on target at 100 yd due to harmonics (whether that's from different seating depth, powder charge, etc doesn't really matter). With most decent rifle barrels, even 2" change would be pretty large - but now think about how tiny the movement at the muzzle has to be to account for 2" at 100 yards. We're talking about 1/30th of one degree; you'd need very precise indicators against a finely graduated background to be able to detect that with one of these high speed cameras.

Some of you are talking about not seeing any harmonics in high speed video, as if you're expecting to see some visible whip. It's not going to move around like an actual whip; we're talking about movement so tiny as to be imperceptible, but that doesn't mean it's not there. The .057" of rearward movement mentioned by Litz is massive in comparison to the miniscule vertical movement of barrel oscillations.

Most of us aren't qualified to disagree with Litz with any real authority on a lot of what he talks about, but in this particular instance I am qualified, and wholeheartedly disagree with his assertion that not seeing harmonics in his cameras indicates it isn't there. It's far more likely he wasn't set up correctly to detect it, much less measure it.

My biggest gripe with what he claimed there, is it is ONE instance for one rifle in one caliber.

He has the be the BIGGEST and loudest mouth shooting at people yelling over and over that 5 shot groups are small sample sizes and mean nothing (which actually irritates the hell out of me). Yet here he literally has a sample of ONE.

If one wants to talk about harmonics and there existence or nonexistence, You would think they would do mountains of testing over various rifles and calibers.

The reason it bugs when people disparage 3 and 5 shot groups is it is very condescending to assume that an individual can't extrapolate data from smaller samples. It really depends on the shooter. Some F class guys can get decent data out of 2 shot groups (I can't). But doing load development for a new barrel I just made or a new rifle, I have no trouble seeing a trend with 3 shot groups and then verifying that data with some 5 shot groups (3-5 5 shots groups usually is enough for the level of accuracy I need).

I myself have a tendency to shoot 4 and a flyer on a regular basis. I know it's me. I know I need to be more consistent. But If I shoot 5 5 shot groups and all 5 have a jagged hole and one flyer, It's me. If all 5 are small clusters, the load is not developed.

 

[Macht]

Whether deliberately or otherwise, it seems like people are missing Bryan's point. He doesn't state that "harmonics"/lateral barrel motion doesn't exist, just that its contribution to dispersion is likely to pale in comparison to interactions with a movement an order of magnitude larger.

There's a reason the Miles to Matches guys frequently mention things like poor rear bag technique leading to shots going high; it's the same thing that drove the design of the "Rokstock" over on Rokslide. In both cases it's dealing with the deflection of the axial portion of the recoil that Bryan is highlighting. The butt dropping in the bag during recoil can induce the same kind of pointing angle error that barrel movement could, and it will inherently be less consistent than a chunk of metal responding to the recoil moment.

To the point that @Yondering and @Slides have brought up, the amount of lateral barrel movement while the bullet is in bore is beyond the resolution limits of the camera Litz is using. That said, it does occur and has been measured using both eddy current sensors and laser interferometers.

@JerkyFreak should probably read more of the material on Kolbe's website. He's pretty clear in stating that centerfire doesn't behave the same way as rimfire. Which makes sense when you realize that rimfire has roughly 1/3 of the chamber pressure and a barrel time roughly triple that of most centerfire cartridges.

 

[brianf]

Whether deliberately or otherwise, it seems like people are missing Bryan's point. He doesn't state that "harmonics"/lateral barrel motion doesn't exist, just that its contribution to dispersion is likely to pale in comparison to interactions with a movement an order of magnitude larger.

There's a reason the Miles to Matches guys frequently mention things like poor rear bag technique leading to shots going high; it's the same thing that drove the design of the "Rokstock" over on Rokslide. In both cases it's dealing with the deflection of the axial portion of the recoil that Bryan is highlighting. The butt dropping in the bag during recoil can induce the same kind of pointing angle error that barrel movement could, and it will inherently be less consistent than a chunk of metal responding to the recoil moment.

To the point that @Yondering and @Slides have brought up, the amount of lateral barrel movement while the bullet is in bore is beyond the resolution limits of the camera Litz is using. That said, it does occur and has been measured using both eddy current sensors and laser interferometers.

@JerkyFreak should probably read more of the material on Kolbe's website. He's pretty clear in stating that centerfire doesn't behave the same way as rimfire. Which makes sense when you realize that rimfire has roughly 1/3 of the chamber pressure and a barrel time roughly triple that of most centerfire cartridges.

Your making too much sense…you’ll be piled on by the flat earthers soon

 

[Slides]

Whether deliberately or otherwise, it seems like people are missing Bryan's point. He doesn't state that "harmonics"/lateral barrel motion doesn't exist, just that its contribution to dispersion is likely to pale in comparison to interactions with a movement an order of magnitude larger.

There's a reason the Miles to Matches guys frequently mention things like poor rear bag technique leading to shots going high; it's the same thing that drove the design of the "Rokstock" over on Rokslide. In both cases it's dealing with the deflection of the axial portion of the recoil that Bryan is highlighting. The butt dropping in the bag during recoil can induce the same kind of pointing angle error that barrel movement could, and it will inherently be less consistent than a chunk of metal responding to the recoil moment.

To the point that @Yondering and @Slides have brought up, the amount of lateral barrel movement while the bullet is in bore is beyond the resolution limits of the camera Litz is using. That said, it does occur and has been measured using both eddy current sensors and laser interferometers.

@JerkyFreak should probably read more of the material on Kolbe's website. He's pretty clear in stating that centerfire doesn't behave the same way as rimfire. Which makes sense when you realize that rimfire has roughly 1/3 of the chamber pressure and a barrel time roughly triple that of most centerfire cartridges.

The majority of people initially using tuners, I'd argue as a tuner, rather than just as a brute inertial mass were F class and bemchrest guys with big, heavy, solid rear bags with significant stock/rider engagement. I'd say for rifles which you might describe as crossover hunter/off the shelf "tactical" muzzle mass is reducing dispersion via brute weight and reducing angular influence of random shooter input dispersion than necessarily bringing bullet exit timing to a wave peak.

 

[LRShooter101]

In terms of the Litz post,
IMHO, the intent of the post is being misinterpreted! I don't believe that he is saying that the harmonics/movement/whip of a barrel has no impact on bullet dispersion.

I believe that he is saying given the example that he posted in the video, there is a bigger chance that actions taken by the shooter during the firing sequence would have a bigger chance of producing bullet impact dispersion versus barrel harmonics/movement/whip.
Quote: "Experienced shooters understand the importance of consistently applied grip, cheek, shoulder and other pressures on the rifle as well as good trigger control and follow thru. These fundamentals aim to make the barrel movement as consistent as possible during recoil/barrel time. In other words, the very fundamentals of marksmanship are based on the sensitivity of precision to the recoil movement during barrel time."
That is because in that particular case, the barrel harmonics/movement/whip are minimal.

IMHO, this issue is also extremely complicated issue that includes a large number of factors that ultimately impact the outcome. If every round fired produced the same internal ballistics, and the bullet behaved the exact same in the barrel every time, then the barrel harmonics/movement/whip would be exactly the same each time. However the internal ballistics and bullet behavior in the barrel are not the exact same unless extreme measures are taken to produce those results. If you look at what goes into Benchrest shooting, then those extreme measures are very clear.

Just my interpretation!

 

[Doom]

For those who deny that barrels vibrate here is a paper on the measurement of longitudinal vibration along with some finite modeling of barrel vibration in a Chinese (?) sniper rifle. This particular model does not include the axial vibration which is the sound pressure wave that that reflected from action to receiver to action over and over again at the speed of sound.

Study on barrel vibration characteristics of typical sniper rifle - Extrica

The firing accuracy of sniper rifle is significantly affected by the barrel vibration induced by shooting load. The barrel vibration is an important parameter needing to be precisely controlled, whose measurement is less studied before. The vertical vibration characteristics of sniper rifle...

www.extrica.com

 

[markl323]

Someone above pointed this out and I could confirm it. The muzzle does move lower. if you watch the video on a big monitor and align one side of a piece of paper with the top of the barrel at the beginning of the footage, you can see a big gap between the barrel and the paper at the end of the footage.

 

[straightshooter1]

Someone above pointed this out and I could confirm it. The muzzle does move lower. if you watch the video on a big monitor and align one side of a piece of paper with the top of the barrel at the beginning of the footage, you can see a big gap between the barrel and the paper at the end of the footage.

Are you talking about recoil movement?

 

[markl323]

Are you talking about recoil movement?

no. something pushes the muzzle down as it recoils.
and now that I'm looking at it again, it also moves back up at the end. It is indeed flexing.
I'll record a video when I get home.

 

[Macht]

For those who deny that barrels vibrate here is a paper on the measurement of longitudinal vibration along with some finite modeling of barrel vibration in a Chinese (?) sniper rifle. This particular model does not include the axial vibration which is the sound pressure wave that that reflected from action to receiver to action over and over again at the speed of sound.

Study on barrel vibration characteristics of typical sniper rifle - Extrica

The firing accuracy of sniper rifle is significantly affected by the barrel vibration induced by shooting load. The barrel vibration is an important parameter needing to be precisely controlled, whose measurement is less studied before. The vertical vibration characteristics of sniper rifle...

www.extrica.com

I don't think anyone in the thread is under the impression that barrels don't move laterally during/after firing.

However, that paper is a complete nothing-burger in the context of the Litz video. They weren't measuring or modeling anything relevent to the in-bore period. That entire paper could be replicated by clamping a barrel in a vice and smacking it with a hammer.

 

[Macht]

no. something pushes the muzzle down as it recoils.
and now that I'm looking at it again, it also moves back up at the end. It is indeed flexing.
I'll record a video when I get home.

Keep in mind that any movement you see is some combination of flex and rigid body motion. You need to be able to measure multiple points to distinguish between the two.

 

[straightshooter1]

no. something pushes the muzzle down as it recoils.
and now that I'm looking at it again, it also moves back up at the end. It is indeed flexing.
I'll record a video when I get home.

OK. Sounds like you're talking about barrel whip???

 

[Slides]

Keep in mind that any movement you see is some combination of flex and rigid body motion. You need to be able to measure multiple points to distinguish between the two.

But the outcome is the combination of the two and always will be.

 

[markl323]

 

[straightshooter1]

This is what I thought you were looking at, having to do with barrel whip. Keep in mind the barrel harmonics are at play long before any of that movement you see in this video.

 

[markl323]

This is what I thought you were looking at, having to do with barrel whip. Keep in mind the barrel harmonics are at play long before any of that movement you see in this video.

yes. but the whip alone can change POI greatly. so if Litz's goal is to prove that barrel's vibrations or movement does not matter. it proves the opposite.

 

[JB.IC]

The only muzzle device that I could imagine lowering SDs would be an adding a suppressor to a rifle that uses a load that has too slow of powder. The powder isn’t fully burned inside the barrel and is still igniting at the crown. Maybe a suppressor can help contain the unignited powder during the transition phase. I have my doubts either way.

 

[markl323]

The only muzzle device that I could imagine lowering SDs would be an adding a suppressor to a rifle that uses a load that has too slow of powder. The powder isn’t fully burned inside the barrel and is still igniting at the crown. Maybe a suppressor can help contain the unignited powder during the transition phase. I have my doubts either way.

yeah...since I made the first post, I watched another EC's podcast and it appears that in the video I posted, he's talking about POI shift not ES/SD. so I misunderstood him.

But regarding unburned powder, that's another interesting point as well. does it cause high ES/SD? from time to time, I hear it does. and to me, it makes sense.

if the barrel is long enough so all of the powder is burned before the bullet exit the muzzle, then the push should be exactly the same each time. but if the barrel is not long enough, then by the time the bullet exits the muzzle, the amount of powder that has been burned up to that point might vary. it could be 91%, 92%, etc. each time and that causes muzzle velocity to deviate.

so if the above is true, then long barrels are inherently better in achieving lowest possible ES/SD, as long as they are long enough for a complete burn.

Mark & Sam made a video on "optimal barrel length" in which he said, if you continue to add barrel length after the powder has been burned completely, then that won't speed up the bullet and will only slow it down due to friction. so is it wrong to say:

whatever your current's barrel length is, if you replace it with a barrel that is 1 inch longer, and still see a speed increase, then that must mean the current barrel is not long enough for a 100% burn. because if it was long enough you would have gotten a speed decrease, not increase. and your ES/SD will never be as low as they could have been with an "optimal length" barrel?

I have asked 3 different gunsmiths and they all told me no. barrel length does not affect ES/SD. but what does everyone think?

 

[tinker]

I would agree a complete burn should be more consistent. I wouldn't so quick to say more barrel length would not add velocity if a complete burn has already happened. Too many variables for that to be true I would think. But I am sure most are aware after a certain point the bullet will slow down as you add barrel length.