Is it possible for a rifle to be more accurate at distance than 100 yards?

[wally]

Obviously you didn't go to the site listed ...

It seems while you may have read it, you didn't really understand it.

From his page "Yawing Motion In General":

imagine to look at a bullet approaching an observer's eyes. Then the bullet's tip moves on a spiral-like (also described as helical) path as indicated in the drawing, while the CG remains attached to the center of the circle. The bullet's tip periodically returns back to the tangent to the trajectory. If this occurs, the yaw angle becomes a minimum.

You seem to be confusing these plots of the "angle" of the bullet tip with changes in the the bullet trajectory. Yes the tip wobbles for a variety of reasons but the real trajectory (path) of the bullet is the path of the CG. These "wobbles" of the tip is a small motion -- a 2 degree angle of a "long bullet" say 1" from tip to CG is only TAN(angle) = wobble/length which for my example is .034" A small fraction of the caliber. To equal .30 caliber the wobble would need to be ~16.7 degrees.

His stuff about "yaw of repose" and "Doppler velocity variations of ~1.6 Hz is only significant at ranges that for 7.62 Nato would be "indirect fire" and the bullet is as much falling as "flying".

I suspect these tip "wobbles" while basically insignificant for punching holes in paper targets account for a significant amount of the variance that results when shooting bullets into ballistics gel where things are non-linear (small changes can have disproportionate effects).

Bullets are stable to within a fraction of a caliber when they exit the muzzle, if they weren't, suppressors would need much larger "holes" to avoid baffle strikes.

 

[Lokichoki]

Simple answer no, the reason it doesnt is because if you get let's say two shot 2" apart at 100yds that 2 different paths 2 different angles that will multiply the farther they travel if there is no discourse or way for it to "get back on track" this is the same with a rock or bullet

 

[CoalTrain49]

I'm in the camp that say it can't happen in a lab or on a range.

The shooter is probably the largest variable so that has to be eliminated to begin with. The gun would have to be fired from some type of fixed rest. I've never read anything published from the scientific community that suggests this is possible. Missiles have to be guided to their targets, bullets have no guidance other than the barrel which they are shot from, so no corrections are possible after the bullet leaves the barrel. Precision can be measured at 200 yards. As range increases that precision has to decrease without guidance. 1" at 200 yards becomes 2" at 400 yards. Ask any 600 yard competitive shooter if they experience any increase of precision as range increases. If that were true they would all be shooting 1" groups. More than likely they are still shooting .5 moa groups on a good day.

If someone can demonstrate the opposite I would like to see it.

 

[wally]

Actually, a bullet from a rifle being fired by a person has a corkscrew path

What on earth ever gave you that idea? The path of a bullet is the motion of its CG (center of gravity). The various corkscrew plots on the net are the angle of the bullet tip relative to the CG. These are generally a small fraction of the caliber and the aerodynamic effects from them are totally swamped by drag (which causes the bullet to slow down with increasing range) and wind (which can move the bullet in any direction) for any "line of sight" (direct fire) shooting.

 

[Mn Fats]

All of the physics are real.... Their effect is minute, but still true... A properly stabilized bullet will settle into a small cone of variation over time... While better optics will increase the accuracy, they have no effect on the bullet and that is how I interpreted the question.

Fats are you a pool player?
Back in the day when I took it seriously, I was known as Mr. C.
Paid for a Brunswick Gold Crown and a Preditor cue...
Steve

Not to deviate from the thread, but yessir, I'm a pool player. Predator 314 is a shaft I'm very familiar with. Was told it couldn't be broke. Split two on the break and both were replaced free of charge. Joss and Mcdermott are my go to.

I dont think so. Doesnt make sense to me why the OP question would ever happen.

Agreed, and if it does, no one wants to try it and get paid. Just speak about it.

 

[CoalTrain49]

What on earth ever gave you that idea? The path of a bullet is the motion of its CG (center of gravity). The various corkscrew plots on the net are the angle of the bullet tip relative to the CG. These are generally a small fraction of the caliber and the aerodynamic effects from them are totally swamped by drag (which causes the bullet to slow down with increasing range) and wind (which can move the bullet in any direction) for any "line of sight" (direct fire) shooting.

Are you saying epicyclic swerve has no effect on a bullets path?

 

[ironworkerwill]

I'm surprised this has went this far. It is possible. It is not probable.

It's down to two factors luck or parallax.

 

[wally]

Are you saying epicyclic swerve has no effect on a bullets path?

Its effects are small and totally swamped by the effects of wind. It is one component of the aerodynamic drift (independent of wind), the direction of which is determined by a left or right hand twist (spin direction). This horizontal drift exists even in perfectly still air but is pretty much a constant bias for a given bullet/velocity/spin and why you'd still need a windage adjustment on your scope even if all your shooting was done in a tunnel (with no ventaliation).


Perhaps Brian Litz can explain it to you:
http://www.appliedballisticsllc.com/Articles/ABDOC104_EpiciclicSwerve.pdf

This paper has some of those nice cyclic plots, what people seem to be mistaking is these plots show the angle of the bullet tip with respect to the bullet center of gravity and the magnitude of the peak deflections are typically less than a caliber. They are not the bulk motion of the bullet whose trajectory is defined by the motion of its center of gravity.

I'm surprised this has went this far. It is possible. It is not probable.
It's down to two factors luck or parallax.

Its gone this far because people are ignoring the fact that the challenge is to prove the claim that the same bullets can fly through a smaller MOA group at a long range than they did at a shorter range. Not that different shot groups could be smaller MOA at longer range than at shorter range for a variety of non-aerodynamic factors (shooter error, parallax, ammo variations, etc.). The claim is that there is some "mysterious" aerodynamic factor that could make the trajectory dispersion (in MOA) be smaller at a longer range than the geometric expectation that if the dispersion is 1 MOA at 100 yards it will be at least 2 MOA 200 yards, or 4 MOA at 400 yards, etc. The so-called "tighter groups after the bullet has gone to sleep" hypothesis.

 

[Mn Fats]

I'm surprised this has went this far. It is possible. It is not probable.

It's down to two factors luck or parallax.

+1 on parallax and luck.
Mod will shut it down pretty quick. Nothing more to add that hasn't been said. Some people KNOW its possible. Some people KNOW it isn't possible. ONE person is giving $$$ out to the man who defies physics. No one, not one has stepped up to Mr. Litz' plate. Why? There's tons of pros and internet guys saying this phenomenon is real but not one has ever showed up to collect the cash. Why not? Lifes too hectic to prove Newton wrong? Until someone steps up to Litz's plate, its all theory just waiting to be challenged.

 

[CoalTrain49]

The claim is that there is some "mysterious" aerodynamic factor that could make the trajectory dispersion (in MOA) be smaller at a longer range than the geometric expectation that if the dispersion is 1 MOA at 100 yards it will be at least 2 MOA 200 yards, or 4 MOA at 400 yards, etc. The so-called "tighter groups after the bullet has gone to sleep" hypothesis.

I'm not disputing Mr. Litzs theory but it depends a lot on bullet design and the individual rifle. Not all bullets are equal in all rifles. The assumption I guess is a shooter and rifle capable of 1 MOA with a certain bullet and load. That's what most try to achieve. The geometric expectation of that combination is 1 MOA. It's possible to shoot 1 MOA at 1000 yards if windage and trajectory are compensated for correctly. A rifle that shoots 1 MOA at 100 yards doesn't equate to 2 MOA at 200 yards or 10 MOA at a thousand. A 1 MOA rifle is 1 MOA at any range within the cartridges capability.

After that it's

It's down to two factors luck or parallax.

 

[wally]

You are correct, I screwed up and typed MOA when it should have been inches or centimeters or some other unit of length in the geometric expectation. Sorry about that, you caught it before I had a change to go back and edit a correction, one of the dangers of posting after midnight and sleeping late

 

[denton]

They are not the bulk motion of the bullet whose trajectory is defined by the motion of its center of gravity.

If you read Bryan's article carefully, he says that the center of mass of the bullet does corkscrew around the trajectory, and he estimates the radius of the corkscrew as less than .050". This is consistent with my source, which estimates the radius for a well stabilized bullet at .009" to .003".

There is a practical difficulty in measuring this effect. That does not mean that it does not happen or that it cannot be calculated from known factors. We know the mass of an electron, and so far as I know, nobody has yet succeeded in getting one onto a scale sensitive enough to measure it. We know the distances to the far galaxies, even though nobody has pulled a tape measure that far.

The calculations say that the effect is real, but much too small to account for rifles shooting 2" groups at 100 yards and 1" groups at 200 yards. So if accounts of this happening are correct, we must look elsewhere for an explanation.

 

[wally]

f you read Bryan's article carefully, he says that the center of mass of the bullet does corkscrew around the trajectory, and he estimates the radius of the corkscrew as less than .050".

If you insist to pick nits and claim some periodic motion less than 1/4 the caliber is "significant" then I guess it really is a "corkscrew" where the wire is thicker than screw diameter -- IMHO hardly what normal people envision when they think of a corkscrew.

 

[denton]

If you insist to pick nits and claim some periodic motion less than 1/4 the caliber is "significant" then I guess it really is a "corkscrew" where the wire is thicker than screw diameter -- IMHO hardly what normal people envision when they think of a corkscrew.

I simply stated that it is real and that it cannot account for anecdotes of rifles shooting better at 200 yards than they do at 100. How you get "significant" out of that or why it's a "nit" and why you would want to disagree with your own source escape me.