Stupid Question Regarding Bullet Stabilization

[onthex]

In the past two weeks I have had two experienced shooters tell me that they have AR15s that group better at 200-300 yards than at 100 because it takes some distance for the bullet to stabilize. That seems to defy the laws of physics to me, but maybe I am the dumbass here. Can someone who is knowledgeable help me here?

 

[diverdon]

They are ignorant liars.

 

[AIAW]

Ahhh the classic "sleeping bullet" theory. Total BS. If it's not accurate at 100 yards it's sure as hell isn't going to correct itself further out (unless there is a tiny pilot inside of those rounds steering it back on trajectory).

 

[Sniper266]

Ive heard this before. When dealing with MOA it doesn’t make any sense. Until someone can print some groups im not buying it.
In other news i was reading up on “over stabilization” and got some interes Conflicting thoughts there.

 

[onthex]

@diverdon I think they are both just ignorant. ? I know that an unstabilized bullet can have a trajectory that curves more than a major league slider, but I cannot imagine it doing it in such a consistent manner that it would actually come back into a tighter group with distance.
@Sniper266 I am with you! I am no ballistic engineer, but I do know that a one inch group at 100 yards should be a two inch group at 200 unless I am missing something!

 

[THEIS]

Hi,

Well let's liven this conversation up some lol...

IF a projectile is at full and optimum stabilization at the muzzle, then how does Doppler show an increase in BC of certain projectiles at around the 650-800 yard Mark?

What is causing the BC increase IF it is not the projectile finally reaching optimum stabilization?

How come that distance is shortened when spinning same projectile 40% faster?

Sincerely,
Theis

 

[Blutroop]

Well this just got interesting..

 

[onthex]

Hi,

Well let's liven this conversation up some lol...

IF a projectile is at full and optimum stabilization at the muzzle, then how does Doppler show an increase in BC of certain projectiles at around the 650-800 yard Mark?

What is causing the BC increase IF it is not the projectile finally reaching optimum stabilization?

How come that distance is shortened when spinning same projectile 40% faster?

Sincerely,
Theis

@THEIS I have no doubt that a bullet may not fully stabilize until it is at some point down range. The question is: Can that result in better groups down range than at closer distances???

 

[THEIS]

@THEIS I have no doubt that a bullet may not fully stabilize until it is at some point down range. The question is: Can that result in better groups down range than at closer distances???

Hi,

Well the question of "Can" is slightly different than "Does it"....

For example: There is a reason the RUAG test facility in Thun Switzerland conducts all their ballistic performance test at 300m. We can debate all day as to why and why not, etc etc.

Caveat: My replies are from specialized weapon systems, specialized projectiles and ELR cartridges, not anywhere in the AR realm of your original question, so take my comments in that context .

IF changing a 338 twist from 9.4 to 7 (While at same time going to a lighter weight projectile) equates to a 6% increase in BC of said projectile then the question of "Can" it result in better groups would be yes in referring the the 9.4 twist because the 7 twist brings the stabilization that much closer to the muzzle aka 100 yard target. Reduce the coning motion of the projectile and you reduce the potential group size.

IF changing a 375 twist from 11.25 to 7 (While at same time going to a lighter weight projectile).....see above in regards to 338 because results are the same

When you spin a top....does it stay in same location while it is stabilizing or once it becomes stable?



Sincerely,
Theis

 

[mgb]

I have a question regarding the alleged improved accuracy at further distances. In order for the bullets to impact the same point down range wouldnt they have to stabilize at the exact same place (thinking three dimensionally here along its path)? Not only at the same distance from the muzzle but at the exact same point in its "wobble". Any deviation would affect the POI the further down range. The bullet may stabilize but cannot correct its flight to improve group size after stabilization. So if the bullet has tight groups down range, theoretically it would have to have similarly tight groups up range as the bullet would have to be flying the exact same path making the exact same deviations regardless of whether its stabilized or not to impact the same point.

 

[sandwarrior]

Theis' analogy of a spinning top is the best example to explain it. It's purely about rotational, or gyroscopic, forces. The top "dances" for a bit then settles down. Bullets don't "dance" as much when they come out of the barrel because they are held in one vector line through the length of the barrel. Think then of starting a top with a container around it, such as a plastic tube. As soon as that bullet finds freedom from the barrel it will vary some. No bullet is ever 100% stable. 99.999~something % stable, but never perfect. The bullet is then affected, more in some cases or less in other shapes, by the oncoming air. Take a thin square of wood and hang it out the window directly into the oncoming air as you drive. Some resistance, but not a lot. Turn the piece slightly and it wants to move the whole board in that direction. The body of the piece of wood is deflecting off the wind and pushing that way.

So, as to the "bullet going to sleep". It's not a theory, it's a scientific proven fact. The difference in forces of the oncoming wind and how gyroscopic forces react to that. If the nose of the bullet is off by a tiny, tiny margin, the oncoming wind will want to deflect that bullet. When the bullet is deflected gyroscopic forces tend to push the bullet 90 deg. from the angle of deflection. That is called gyroscopic precession. Precession never pushes the bullet out of place as far as the original deflection force, as it's spread over a larger area of rotation than the original deflection. Therefore over time and distance precession decreases. As, it becomes smaller and smaller, the bullet appears to go to sleep.

Now, each precession movement in reaction to each deflection movement is at different angles. So, those forces offset each other....mostly. And, remember that movements start very small to begin with. A bullet coming out of a barrel sideways isn't ever going to stabilize. But, tiny movements will flatten out.

Group sizes: You need to separate angular size, i.e. moa and mil vs. physical size. At a bullets most unstable region of flight, you will have a large spread, both physical and angular. As the bullet stabilizes in flight more it will mostly remain on the angle it has taken. But, it's not going to physically spread from that angle. Because of a difference, bullets will take slightly different angles. That will obviously generate a larger angular group. With a good barrel and load however, the angular difference will be minimized and the physical difference will be minimized. Meaning the quicker a bullet goes to sleep, the more accurate your physical size is going to be. You can have a wide angular measurement at short range and the bullet stabilizing (deflection and precession forces balancing) creating a situation where Angular measurement will decrease while physical measurement slightly (less than angular) increases.

That's it in the smallest nutshell I can put it. Feel free to burn the wagon down and continue to shoot the way you always do.

 

[Hollywood 6mm]

I'm pretty sure that Bryan Litz has a standing offer of a large sum of cash for anyone that can come to the AB lab and prove that a rifle/ammo combo can consistently print a smaller (angular) group at distance than up close. The fact that I have yet to even hear of anyone attempting his challenge should speak volumes.

 

[THEIS]

Hi,

Would he still make that offer in a 1000m environmental controlled shooting tunnel so that the external environmental conditions can be ruled out as a factor in the angular groups?
Or
Would he settle for the Yuma Proving Grounds Doppler radar data showing the "bullet sleep" distance variations based on twist rates, etc etc?

IF so have him send me the details of his "standing offer".

Sincerely,
Theis

 

[Hollywood 6mm]

Hi,

Would he still make that offer in a 1000m environmental controlled shooting tunnel so that the external environmental conditions can be ruled out as a factor in the angular groups?
Or
Would he settle for the Yuma Proving Grounds Doppler radar data showing the "bullet sleep" distance variations based on twist rates, etc etc?

IF so have him send me the details of his "standing offer".

Sincerely,
Theis

If I remember the details (it's been a bit) the plan was to use target frames with sheets of paper in the frames out to a set distance (600y, I think), and one string being fired through all of the frames simultaneously. If the later frames showed less angular dispersion, you win.

I'm sure you could email him through the AB website and take him up on it.

 

[Yellowfever440]

Wow, I think you guys are telling me that i really can "bend bullets" or shots like they do in that movie WANTED. That is what your getting at right? LOL

 

[THEIS]

Hi,

Ah Gotcha....Yaw Card Method.
NDIA and Arrowtech has already spent the millions of dollars proving and disproving the effectiveness of Yaw Cards.

I have a little more respect of results from say:
A continuous wave Weibel radar such as this one:

Or a Cinetheodolites machine as this one:

Both of those test units are available for use at Overberg Test Range.

Sincerely,
Theis

 

[Sheldon N]

I don't buy into the whole "bullet goes to sleep" or stabilizes out further theory. However I do believe positive compensation is a real thing and is proven in 1000 yard benchrest shooting.

Positive compensation in a nutshell = barrel is in motion during the firing process on an upward sweep due to the harmonics of the firing process. A bullet going slightly faster exits the muzzle slightly sooner and prints slightly lower at 100 yards. A bullet going slightly slower exits slightly later and prints slightly higher at 100 yards. The difference in POI at 100 yards gets cancelled out at 1000 yards as the trajectories of the faster and slower bullets converge.

Proof is in the fact that guys are shooting groups with tighter vertical than the ballistics says is possible. Some of the world record setting 1000 groups might have an ES of 15 and print a tighter waterline than trajectory calculations says is possible. And some groups that have an ES of 3 might suck at 1000 yards in comparison.

This is on the bleeding edge of accuracy and is only really exploited by people who do a ridiculous amount of testing at 1000 yards in perfect conditions from very consistent and repeatable shooting rests. No, you can't use it to say that your crappy 3/4 MOA group from a hunting rifle hammers 2" at 1000 yards all day long.

 

[Lowlight]

human factor

It's recoil management for 99% of the cases where precession is observed by the shooter.

In order to truly prove this, the system has to be in a fixture and the human factor eliminated. Then you have to do everything you can standardize the cartridge load. The MV, Seating, etc all have to be perfect or else, you have issues in the testing.

It's a visual, subconscious thing. people are adverse to recoil shoot crappy close in but better farther out is a brain thing with Perception. We perceive the movement more close in, and less at the farther distances so they shoot better. The recoil in the scope is more pronounced the closer you are, which is why most of the time it is discussed it is with magnum caliber rifles.

Rarely do you hear about this with light recoiling rifles?

Runout has a part of this as well, I have been aware of tests where they noticed the BC changing shot to shot and the paper impact target had the points of the bullet hitting off center. Bullet Runout can cause this, and as noted above it is tiny. BC changes will happen with every single shot if the conditions change enough. Even Tubb spoke about it on my Podcast where with an SD Of 0, he still sees BC changes to varying degrees.

We cause a lot of the noticeable stuff than the science does, sure the coning will vary from shot to shot, but how does that fit into the shooter's ability to group? Most of the time the variations are noise within the group size.

 

[onthex]

@THEIS Thank you for the file you sent me. (Or maybe I should say FU since I stayed up until 3 in the morning trying to digest it Friday night! LOL) It shed a great deal of light on the subject. After reading it I consulted with an old friend who is an aerospace engineer, and he helped put it into terms that I could understand.

@sandwarrior You helped even more by taking what he told me and condensing it into a nutshell.

Here are my takeaways from all this info:

1) Vaughn's definition of "coning motion" is flawed because it only considers the motion of the nose of the bullet and does not consider the motion of the tail around the CG. He also fails to consider pitch, yaw and exterior factors such as wind.
2) No rifle and bullet combination will EVER result in physically smaller groups downrange. That is to say that it is impossible for a five shot group that measures 2 inches at 100 yards to shrink to 1 inch at 200 yards.
3) However, as deflection and precession forces become balanced it is possible for angular dispersion to decrease. As this occurs the physical measurement of the group will continue to grow, but at a slower rate than earlier (and greater) angular dispersion would have indicated.

Now, for the most part I am not that bright (and I am certainly not a rocket scientist), so I will do my best to explain what I think this all means in common sense terms and apply that to my original question: Can a rifle group better at 20-300 yards than at 100 yards? Well, that depends on your definition of "group better". If you define a better group as physically smaller, e.g. 2 inches at 100 yards versus 1 inch at 200 yards then the answer is definitely NO.

However, if you are defining "group better" in terms angular measurement, or in simpler terms how well a group holds together then the answer in theory is YES. Here is why: Most of us (myself previously included) logically think that if a gun shoots a group that measures one inch at 100 yards that same group will grow proportionally to six inches at 600 yards, and if the angular measurement remains unchanged from 100 to 600 yards that would be correct. However, if as the bullet stabilizes the angular measurement decreased then theoretically a one inch group at 100 yards might only become a three inch group at 600 yards.

Of course, the opposite can be true as well. As velocity and spin rate decrease bullet stabilization falls apart, so a gun could produce a super tight group at 100 yards, but the same gun/ammo combo could look like shit at 500 if the bullet starts to de-stabilize early as it travels down range. A great real world example of this would be an AR15 in 5.56 NATO that I own sporting an 18" barrel with a 1:9 twist. This gun is an absolute tack driver at 100 yards with bullets from 40-77 grains in weight, and I consistently shoot steal out to 450 yards with this gun using Beck Ammunition 55 grain VMAX rounds. However, at 450 with 77 grain Sierra Match Kings I cannot hit an IPSC consistently to save my life because that 1:9 does not spin that bullet fast enough for it to remain stabilized over distance.

So let's go back to the original question and consider it in the following hypothetical scenario:

Shooter A has a gun/load combo that consistently shoots 5 shot groups measuring 1/2 inch at 100 yards and just over 3 inches at 600 yards. This occurs because his combo produces bullet stabilization very early resulting in an angular measurement that remains constant over several hundred yards down range. Shooter B has a gun/load combo producing groups that are usually in the one inch range at 100 yards but that consistently stay around 3 inches at 600 yards. If I understand what I have learned from @THEIS , @sandwarrior and my buddy correctly this is possible because he has a combo that results in the bullet having to travel further before achieving optimum stabilization, but, once his bullet stabilizes angular measurement improves significantly resulting in groups that grow physically larger down range, but that also have less dispersion than one would logically expect based on his group sizes at close range.

I guess that all of this means that if a persons definition of "grouping better down range" means tighter groups in regard to what would be expected based on his groups at 100 yards then he would be neither ignorant or a liar to say that "my gun groups better 300 yards than it does at 100".

Thoughts???

 

[Sheldon N]

Thoughts???

I think the idea of bullet stabilization being any sort of "improving" factor is a bit far fetched. Whether the bullet is wobbling or flying straight and stable the center of gravity of that bullet is going to follow the predicted trajectory. The only external factor is the aerodynamic interface as it flies through the air.

I don't think of a wobby bullet as a corkscrewing bullet. The "wobble" is SOOOO much faster than the trajectory travel of the bullet. The bullet is spinning at 250k RPM or thereabouts or roughly one full turn for every 7 or 8 inches of travel. Compare that to a football where it is maybe 600 RPM and travels 5 feet or more per revolution. Even if the bullet nose doesn't point perfectly straight it's spinning so fast that any sort of "corkscrew" effect is not going to happen where the bullet comes back onto target like a controlled curve ball from a pitcher. Rather I'd see it as a bullet that flies in less than predictable fashion due to the aerodynamic effects of unstable flight, particularly since the nature of the "wobble" from shot to shot is likely inconsistent.

The most common sense argument against the idea that angular improvement in group size due to bullet stability is possible is this..... A reduction in a destructive factor (bullet instability decreasing as the bullet flies) is NOT the same as an improving factor. Chaos does not lead to order.

Some other things to consider are this... the starting point of the trajectory of each shot is NOT fixed. The barrel moves during firing, and there can be a different muzzle exit position from shot to shot. Secondly, velocity can be different from shot to shot, and these two factors can be intertwined. That's why something like positive compensation can be possible while the bullet stabilization theory is IMO implausible.

 

[sandwarrior]

I think the idea of bullet stabilization being any sort of "improving" factor is a bit far fetched. Whether the bullet is wobbling or flying straight and stable the center of gravity of that bullet is going to follow the predicted trajectory. The only external factor is the aerodynamic interface as it flies through the air.

I don't think of a wobby bullet as a corkscrewing bullet. The "wobble" is SOOOO much faster than the trajectory travel of the bullet. The bullet is spinning at 250k RPM or thereabouts or roughly one full turn for every 7 or 8 inches of travel. Compare that to a football where it is maybe 600 RPM and travels 5 feet or more per revolution. Even if the bullet nose doesn't point perfectly straight it's spinning so fast that any sort of "corkscrew" effect is not going to happen where the bullet comes back onto target like a controlled curve ball from a pitcher. Rather I'd see it as a bullet that flies in less than predictable fashion due to the aerodynamic effects of unstable flight, particularly since the nature of the "wobble" from shot to shot is likely inconsistent.

The most common sense argument against the idea that angular improvement in group size due to bullet stability is possible is this..... A reduction in a destructive factor (bullet instability decreasing as the bullet flies) is NOT the same as an improving factor. Chaos does not lead to order.

Some other things to consider are this... the starting point of the trajectory of each shot is NOT fixed. The barrel moves during firing, and there can be a different muzzle exit position from shot to shot. Secondly, velocity can be different from shot to shot, and these two factors can be intertwined. That's why something like positive compensation can be possible while the bullet stabilization theory is IMO implausible.

It's clear then you don't understand gyroscopic precession, whether it pertains to bullets or not. It pertains to ANY spinning mass. It's reaction is very predictable. And, it doesn't take a lot of side force to create movement in a general 90 deg direction from the direction a force was applied.

Yes, the bullet wants to follow it's intended trajectory. External forces, i.e. deflection, WILL move it. And while it's spinning fast, the force will still act. And, the precession will still be a result.

I think the most misunderstood part of this is when bullets go radically unstable. You aren't going to get a super group @ 1k from a keyholed 3" group @ 100. But, pull your targets that you zero with @ 100 using uber VLD type bullets and measure the hole each bullet makes. If they make one hole, take five of them and shoot five individual holes. You might need to blow them up a number of times, like benchrest records are measured, to see the keyholes. They are there. You just don't see them on a big scale.

 

[Sheldon N]

My comments were intended to entirely set aside the issue of external forces like wind. Yes, I get that gyroscopic precession is a thing. I'm talking about how the bullet flies through calm air. Gyroscopic precession would still be involved in spin drift, but that goes back to how the bullet performs as it cuts through the air, both aerodynamics and the bullets response to them which includes the gyroscopic forces.

For me the basic logic goes back to chaos vs order. Just because you reduce the disruptive influece of a wobbly bullet, ie it stabilizes after a couple hundred yards, does not mean that it is going to be somehow drawn back into a small group at the center of point of aim.

 

[hlee]

Yep, if a bullet is off by “x” angular measurement at “y” distance, what causes it to correct its course and be off by less than x at greater than y? There is no pilot in the bullet. Bullet stabilization causing smaller groups at longer distances doesn’t pass the “sniff test.”

 

[sandwarrior]

My comments were intended to entirely set aside the issue of external forces like wind. Yes, I get that gyroscopic precession is a thing. I'm talking about how the bullet flies through calm air. Gyroscopic precession would still be involved in spin drift, but that goes back to how the bullet performs as it cuts through the air, both aerodynamics and the bullets response to them which includes the gyroscopic forces.

For me the basic logic goes back to chaos vs order. Just because you reduce the disruptive influece of a wobbly bullet, ie it stabilizes after a couple hundred yards, does not mean that it is going to be somehow drawn back into a small group at the center of point of aim.

It's not so much that accuracy increases, it just gets to a point where it doesn't get worse. the damage has been done, so to speak, in the first stages of a long range flight.

Reiterating, a bullet that leaves a visible key hole ain't ever gonna come back into and make a better angular group. I'm talking about a 1/2" group being a 2 3/4" group @600 or a 4 1/2" group @ 1k. External forces i.e. WIND are going to make for more variance than gyroscopic precession. The size of the variation possible isn't much. Because the physical will always grow... If it doesn't, stop shooting and run down and get a lotto ticket.

Where it really matters is benchrest. Where groups are not measured by 1/4 moa, 1/2 moa or tenths of mil, they are measured in thousandths. And, FWIW they don't use long range bullets to shoot groups at short range. Specifically because the stability is much better with a different style of bullet.

As to the OP, the two guys shooting AR's I'd have to agree with most posting on here that they don't even have any quantifiable method of measuring it. Only that it exists. I think where most people have heartache with it, is it gets used as an excuse. In that case, it's not a legitimate reason for shooting all over the place if you can do better.

 

[sandwarrior]

Do we have a new version of SH here? I see "Belligerants" listed under a bunch of our names?....

 

[onthex]

So @sandwarrior if I understand you correctly it is theoretically possible for a gun/load combo that produces a 1/2 inch group at 100 yards to only make a 2 inch group at 600?

 

[sandwarrior]

Theoretically. And remember when theories come true on the first try, run down and get yourself a lotto ticket.

Between the forces of deflection and precession, it is possible. In a perfect world, it's more possible that this phenomena can be seen. As I stated above, it's a small angular improvement, not a great one. But, the physical group size will always grow. The bullet wants to follow the original vector the barrel sent it on. Once the bullet 'settles' accuracy may not get any worse, but it certainly won't get any better. It has already departed from it's original vector. But, still wants to follow that vector.

In the past, the exaggerations are that one could shoot a three inch group at 100 and get a two inch group at 500. That is completely not true. Unless, you didn't make some bizarre wind call....that you didn't see.

In all honesty, in all the variables of shooting this is a minor one. Splitting the difference between potential physical and angular groups. it's small compared to what HMFIC said and that is people aren't applying all the fundamentals. It's about like spin drift and coriolis effect. They don't mean much unless you really get out there. And, there's so much more to go wrong with your shot than this issue.

 

[hlee]

If you fire 5 at 100 and 5 at 600, it is statistically possible that the 5 close range will have a larger angular group than the 5 long range. Just by chance- because 5 an arbitrary number and not necessarily representative of the batch. But, as sandwarrior said, for those 5 close range bullets, the damage is done. If you were to track their flight to 600, you would not see them printing closer together than at 100. If the group was 1/2 moa at 100, the best you can hope for is "no further spread," but they are already off course. At 600, you could hope for a 1/2 moa group (+/- some measurement error).

An analogy... Has anyone else driven I-80 through Nebraska? A flatter and straighter road you're not likely to find. It's so straight, I joked you could take a nap and not hit the ditch. Let's assume you tried that. You get the vehicle lined up (zero wind day), put the cruise on, and dose off. At some later point you wake to find that you are slowly pulling toward the ditch (instability caused variance in trajectory). If you eliminate the pull, putting your tires directly in line with the vehicle (no further degradation) you are still headed for the ditch- just not as quickly. To get back on course with the road you need to correct the pull, then realign the vehicle with the road.

Another analogy... Let's assume we have a laser that creates daylight visible spot at 1000 yards and does not experience any diffraction over that distance, nor any dispersion in the signal. Now, from 100 to 1000 yards we stretch Saran Wrap to act as a target for our laser. But, our Satan wrap is optically transparent and does not cause any deflection or degradation of our laser. Now, we aim the laser down range at our field of Saran Wrap targets. From 100 to 1000 yards, the laser hits the target at a spot we can mark. This state represents a perfectly stable projectile- absent any outside forces, flying from 100 to 1000 yards. If we remove our laser and replace it with a new laser with equivalent qualities and align it with the 100 yard spot, it will also be aligned with the 1000 yard spot. Every laser beam (bullet) hits the same spot from 100 to 1000 yards. Now, some yahoo walks by and bumps our laser. We can all agree that a laser is a straight beam of light that is not affected by gravity, wind, or spin drift; correct? Ok. We measure the deflection of the laser at 100 yards. 1 moa. At 200 yards, 1 moa. At 1000 yards, 1 moa. The bump represents initial instability that causes a variation in the point of impact relative to the point of aim. Once the last is off course, it is off course into infinity. In order to bring the impact point back to the aim point, we must make a correction.

Once the vehicle is off course it is off course. Once the laser is off course, it is off course. Once the bullet is off course, it is off course. None know where they were aimed, nor where they are expected to go. To get them back on course requires an active correction, but there is no mechanism to accomplish this with a bullet in flight.

I fully agree that a "sleeping bullet" could minimize the damage to its flight path (1 moa variance at 100 and 1000 y for example). But, to suggest that "sleeping" can cause the bullet to pull back on course doesn't pass the sniff test.

 

[Sheldon N]

The bullet wants to follow the original vector the barrel sent it on. Once the bullet 'settles' accuracy may not get any worse, but it certainly won't get any better. It has already departed from it's original vector. But, still wants to follow that vector.

Once the bullet has left the barrel, deflected from the 100 yard bulls eye trajectory due to instability, isn't that now a new vector? It's not going to return to the original vector because the travel off trajectory has created new momentum for the bullet away from the bulls eye. It would need a new, counteracting force to put it back on trajectory.

Or put another way... if the wind is only blowing in the first 100 yards, does the bullet stop drifting once the wind stops blowing?

 

[Nishgriff]

our Satan wrap is optically transparent

I was DYING laughing!

 

[onthex]

Talk about confusing shit! OK, so I think the consensus is that 1/2 MOA at 100 is gonna be 1/2 MOA or worse anywhere down range. That makes sense to someone in my pay grade.

I still believe that the two guys that have told me this are not ignorant liars. One is a retired military sniper who now works in the shooting industry, and the other is an engineer and former NASCAR team owner. I think both of these guys really do believe that they get better groups down range out of a certain gun, but it is more likely due to the human factor as our HMFIC @Lowlight suggested. As a matter of fact, after wading through all of this and reading several hundred pages of research data I am pretty sure Frank has the best hold on this of all!

 

[j-huskey]

Albert Einstein proved some people wrong, if the theory is always correct, bumblebees cant fly, and b52's shouldn't be able to take off.

I've seen that weirdness b4 on a couple of bullets with sleep apnea, argued it b4 on SH way b4 Scout and Brian Litz, and gave up arguing.

Damn flying bumblebees...

??????

 

[THEIS]

Hi,

Lets try and simplify this concept a little more.

I think some are thinking that we are saying a 3" 100m group can turn into a 1" 500m group..That is NOT it at all.

What we (Well ME) are trying to say is that as LL said it all can be a wash when we add human factor but that does not mean the concept does not happen

Think of it like this:
In the image below we have a projectile that is 1.25" in length.
Location A is 100m
Location B is 300m
Factor in the length of the projectile and the rotational cone area; is the group size at location A larger than location B?
YES I am aware that we are not bringing in any environmental conditions into question; but rather simple question based on distance of achieved full stabilization.
YES I am aware the image is not to scale and exaggerated to highlight the subject in question.

Sincerely,
Theis

 

[Lowlight]

the problem is, these out of scale images in part, the coning stuff is microscopic. This wobble is so small, it's not like a crossbow bolt where you can see the back end spinning.

When this stuff grows to a noticeable portion, the bullet is usually out of sorts. You can see the tips and how they hit even on steel with a Hornady bullet, the plastic makes a visible indent that you can see on the plate. We are really talking about one side of the center or the other, and not so far off center that it causes the bullet to hit sideways. You'd see random oblong hits on paper or steel.

The best way to see what is going on is not from group size, that is all about the shooter, but the BC values. You have to actually do the math and see if the BC goes up or down. then you have to look at the various results of a BC Test. That is why people will say, show me, because they know it's so small you can't actually demonstrate it without keyholing the bullet.

if you see it, it's you, that is the easiest way to put it. If you have a flyer you can almost point to this, but with flyers, you see it in a random way and not a consistent group value way.

It's like when guys talk about canting the rifle, they use 5 degrees which is huge and very user noticeable. That is no our issue, it's the .5 degree variation we put into each shot that messes with our group. to the point, I can notice a progression of canting downrange at the target. There is a pattern and I can see that pattern on the paper.

For the coning theory information to be considered, I highly doubt you are seeing it unless you can repeatedly put down .25" groups or better. And by repeatedly, I mean every single time.

 

[Sheldon N]

Location A is 100m
Location B is 300m

I am confused. Is there a second shooter on the grassy knoll?

 

[j-huskey]

There are three, Sheldon, three...?

 

[sandwarrior]

the problem is, these out of scale images in part, the coning stuff is microscopic. This wobble is so small, it's not like a crossbow bolt where you can see the back end spinning.

When this stuff grows to a noticeable portion, the bullet is usually out of sorts. You can see the tips and how they hit even on steel with a Hornady bullet, the plastic makes a visible indent that you can see on the plate. We are really talking about one side of the center or the other, and not so far off center that it causes the bullet to hit sideways. You'd see random oblong hits on paper or steel.

The best way to see what is going on is not from group size, that is all about the shooter, but the BC values. You have to actually do the math and see if the BC goes up or down. then you have to look at the various results of a BC Test. That is why people will say, show me, because they know it's so small you can't actually demonstrate it without keyholing the bullet.

if you see it, it's you, that is the easiest way to put it. If you have a flyer you can almost point to this, but with flyers, you see it in a random way and not a consistent group value way.

It's like when guys talk about canting the rifle, they use 5 degrees which is huge and very user noticeable. That is no our issue, it's the .5 degree variation we put into each shot that messes with our group. to the point, I can notice a progression of canting downrange at the target. There is a pattern and I can see that pattern on the paper.

For the coning theory information to be considered, I highly doubt you are seeing it unless you can repeatedly put down .25" groups or better. And by repeatedly, I mean every single time.

Exactly why I said this would really matter in benchrest and maybe not so much in tactical. In benchrest we are able to take out so much of the human element. Not so in tactical shooting. As this phenomena does exist, it's hard to quantify when the real impetus (here) is to improve upon the human element in shooting. This issue, in tactical shooting, is a smaller issue than human factor. And, again to the OP, the two guys not shooting AR's at close range, because they won't get a good group is BS. You should always be able to shoot the best group possible from whatever rifle you bring. It's not bullet going to sleep that will make you shoot crappy groups in a tactical comp. It's lack of marksmanship basics. In Benchrest, though, I'm talking closer to .1's. .2's is the minimum and .25's don't cut it. For what we do in long range, .25 is outstanding. That difference alone should say something about gyroscopic stability.

On the flip side of this where we shoot short range accuracy bullets, then yeah, two AR-15's shooting long range bullets aren't going to really get competitive. they will be much more competitive at long range. Short, flat base bullets are going to be easier to stabilize out of a slow twisted barrel. Therefore relieving a lot of gyroscopic precession. You don't see the coning there, unless you get microscopic. But, they don't reach long as they lose more stability over time/distance. They lose the most stability when they reach the transonic range.

 

[THEIS]

There are three, Sheldon, three...?

Hi,

Still got the shovel??

Sincerely,
Theis

 

[j-huskey]

Que' ?

Backhoe for small jobs, trackhoe/excavator for larger jobs,
Ditched the shovel...

 

[supercorndogs]

Albert Einstein proved some people wrong, if the theory is always correct, bumblebees cant fly, and b52's shouldn't be able to take off.

I've seen that weirdness b4 on a couple of bullets with sleep apnea, argued it b4 on SH way b4 Scout and Brian Litz, and gave up arguing.

Damn flying bumblebees...

??????

https://www.livescience.com/33075-how-bees-fly.html

How bees fly.

 

[j-huskey]

https://www.livescience.com/33075-how-bees-fly.html

How bees fly.

They dont fly well when we shoot them with rat shot in a 22 pistol, barn pests, they crash and roll and the fire ants get fat.

 

[just browsing]

Y’all are a bunch of nerds.

If you hit what you’re aiming at who gives a damn what some internet chat board guy says about how stable your bullet may or may not be.

The target tells all.

 

[supercorndogs]

They dont fly well when we shoot them with rat shot in a 22 pistol, barn pests, they crash and roll and the fire ants get fat.

http://mentalfloss.com/article/84992/why-dont-ants-gain-fat

Why ants don't get fat.

 

[j-huskey]

http://mentalfloss.com/article/84992/why-dont-ants-gain-fat

Why ants don't get fat.

Remind me never to wager $ against you...????
Even when just poking the bear in fun.

 

[YF12A]

Learned a lot here and I thank you all very much for this information, even with the fact I am going to have to read it a couple of times to fully get it. Just like life, the more you think you know, the more there is to learn.

 

[sandwarrior]

https://www.livescience.com/33075-how-bees-fly.html

How bees fly.

Who is this fucking retard Joe Calamia retard that pretends to know how airplanes fly. They DON'T push air downward, The camber of the wings creates a low pressure above the wings. A propeller moves a plane through the air by creating a low pressure in front of the prop. It's the camber over the top of the wing that provides lift.

As to the bee, it flies just like a plane or a bird. It flaps it's wings so that the camber over the top of their wings provides lift. They change the angle of the flap to hover or fly forward.

 

[Snuby642]

I have done a few tests and found no difference in stability noteworthy.

By the time I reach the berm to dig them out they're all stable.

 

[sandwarrior]

I have done a few tests and found no difference in stability noteworthy.

By the time I reach the berm to dig them out they're all stable.

Is that like catching a knuckleball? ...Wait until it stops rolling then pick it up?

 

[supercorndogs]

Who is this fucking retard Joe Calamia retard that pretends to know how airplanes fly. They DON'T push air downward, The camber of the wings creates a low pressure above the wings. A propeller moves a plane through the air by creating a low pressure in front of the prop. It's the camber over the top of the wing that provides lift.

As to the bee, it flies just like a plane or a bird. It flaps it's wings so that the camber over the top of their wings provides lift. They change the angle of the flap to hover or fly forward.

You are mixing up the writer of the article, with the writer of the published scientific study he is writing about. Written by "Michael Dickinson, a professor of biology and insect flight expert at the University of Washington."

"An airplane's wing forces air down, which in turn pushes the wing (and the plane it's attached to) upward."

I am not sure how you are taking issue with what they are saying?

 

[sandwarrior]

You are mixing up the writer of the article, with the writer of the published scientific study he is writing about. Written by "Michael Dickinson, a professor of biology and insect flight expert at the University of Washington."

View attachment 7024944

"An airplane's wing forces air down, which in turn pushes the wing (and the plane it's attached to) upward."

I am not sure how you are taking issue with what they are saying?

There is a pressure differential. I take issue with the dumbass saying the wing pushes air down. It's the low to high pressure differential from the top of the wing to the bottom of the wing. It's called Bernouli's principle. It's the low pressure over the wing that creates the lift.

What you are showing is a wing during climb, which pretty much equates to drag. Or, an elevator lifting the rear of the aircraft so it will descend.

Read this.
http://www.csun.edu/scied/4-discrpeant-event/Bernoulli_effect/discrepant_event.html