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

Bart B. said:

Nowhere have I seen Brian Litz comment on the information in those links. There's no evidence he has challenged its authenticity. Especially that shown in Varmint Al Harrel's pages at

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I've seen his comments.
The fact you haven't doesn't mean he didn't say it, and again, no one has taken him up on the challenge, so you could be the first.
More theories aren't "proof" no matter what "Varmint Al" has on his site.

(Your first link talks about barrel vibrations and the second is about calling Coyotes, so they aren't relevant)

"Vibrations of Rifle Barrels. Mallock, A Proceedings of the Royal Society of London (1854-1905). 1901-01-01. 68:327–344"

Is not about calling coyotes.

Both links are real; not theories. I understand why some don't believe either.

if you have a load with a large velocity variance, groups shot will have a large vertical dispersion (long range shooters like low extreme velocity spreads). the slower shots will exit the muzzle later and higher (due to the greater muzzle rise due to recoil) than faster shots (due to the lesser muzzle rise due to the same recoil). at some point in the bullets trajectory curve, the slow and fast shots will intersect (the slower shot trajectory starts higher but drops faster than the faster bullet). i think bart b. referenced a test of this done about a hundred years ago by the british using an smle and military ammo.

result: crappy groups at 100 yards and good groups where the slow and fast shot trajectories intersect.

regarding the bullet and "going to sleep": bullet yaw and bullet precession will decrease the farther from the muzzle because the bullet is self-stabilizing regarding these two attributes. spin a top on the floor and you will see what i mean.

murf

Jim Watson said:

The bullet is not going to orbit around outside its trajectory.

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Precession motion as torque excerted by the bullet weight in the direction of the spin against decelerative torque of air resistance and aerodynamically variable axis (spin effect) certainly would not be limited to perimeter of linear trajectory. Add even a small amount of (inherent) bullet instability and there's no reason the deviation couldn't be multiples of the physical diameter of a spinning bullet. There's no denying the effect on POI exists in vivo so there must be a plausible explanation for it; whether or not it's this one, I don't know, but I'd really like to hear about it if you have a better one.

Interesting discussion that got me to thinking. A rifle supposedly shooting 2 moa at 100 and 1.5 moa at 200 yards is said to more accurate (relative accuracy) at 200 yards even though the group size is actually larger (actual accuracy). So you don't actually have a greater chance to hit the bullseye at 200 yards than you do at 100 yards.

The only way I could see this being tested would be to take the shooter out of the equation. Set up a barrel on testing machine that anchors the barrel firmly into a fixed position and place targets at 100 yards. Fire a group. Without moving the barrel, place targets at 200 yards and fire a group.

I have seen shooters do better at distance than close up, but the difference wasn't because of ballistic issues. It was all shooter. Give the gun to a different shooter and get a different result.

hq said:

Let's try this one more time: the median flight path doesn't CHANGE. The gyroscopic stabilizing force of bullet spinning creates an in-flight deviation pattern that can be described as a flight path -centric "corkscrew". The amount and direction of deviation can vary in function of time and distance, creating a possibility that the deviation is smaller at a longer distance. Carl N. Brown described this exact phenomenon (epicyclic swerve, a term that I didn't remember) in post #39 above.

Do you understand it now?

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You're saying it's kind of like something being flushed down a toilet? At first it corkscrews in large circles, but as it gets closer and closer to the bottom of the "bowl" those circles get tighter and tighter as the bullet stabilizes?

Double Naught Spy said:

A rifle supposedly shooting 2 moa at 100 and 1.5 moa at 200 yards is said to more accurate (relative accuracy) at 200 yards even though the group size is actually larger (actual accuracy). So you don't actually have a greater chance to hit the bullseye at 200 yards than you do at 100 yards.

The only way I could see this being tested would be to take the shooter out of the equation. Set up a barrel on testing machine that anchors the barrel firmly into a fixed position and place targets at 100 yards. Fire a group. Without moving the barrel, place targets at 200 yards and fire a group.
.

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Sure you do. The bullseye is bigger. NRA target scoring rings are angular. F class gets you a one MOA ten ring at all usual ranges.

The only way I could see this being tested is to set up a tissue paper (or acoustic) target at 100 yards and a fixed target at 200 yards, better 300 or more.
That way you are registering the SAME BULLETS. Successive groups with different bullets are going to vary, you would have to shoot a great many rounds to build up any statistics. Oh, wait, Mr Litz has already proposed this with no takers reported.

bassjam said:

You're saying it's kind of like something being flushed down a toilet? At first it corkscrews in large circles, but as it gets closer and closer to the bottom of the "bowl" those circles get tighter and tighter as the bullet stabilizes?

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In very simplified terms, yes, even though a more relevant comparison would be a spinning top. When you spin one, it circles in large arc at first until gyroscopic forces overcome the destabilizing effect of starting the spin by hand. After a while it settles down to a more stable spin until it slows down, loses momentum and gyroscopic effect, starts to wobble and falls over. Deceleration force due to wind resistance has the same effect as gravity and base support on a top. The effective distance between the center of gravity and the intersection of the rotational axis of the bullet and median flight path gets shorter and the angle between the two gets linearly smaller in function of stabilization.

As I pointed out earlier, this is just a theory based on physics affecting a rotating object but it's probably the most plausible one explaining the phenomenon.

OOPs. my mistake. Deleted.

hq said:

In very simplified terms, yes, even though a more relevant comparison would be a spinning top. When you spin one, it circles in large arc at first until gyroscopic forces overcome the destabilizing effect of starting the spin by hand. After a while it settles down to a more stable spin until it slows down, loses momentum and gyroscopic effect, starts to wobble and falls over. Deceleration force due to wind resistance has the same effect as gravity and base support on a top. The effective distance between the center of gravity and the intersection of the rotational axis of the bullet and median flight path gets shorter and the angle between the two gets linearly smaller in function of stabilization.

As I pointed out earlier, this is just a theory based on physics affecting a rotating object but it's probably the most plausible one explaining the phenomenon.

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I don't think a top spinning on a table in a 2D world, with no momentum along the Z axis, translates to a bullet moving through a 3D world where it does have momentum along that 3rd axis. Either way, a top spinning like you describe doesn't go in a circular path wider than it's own diameter. So a .30 cal bullet under the same affect would only force a change of roughly 0.3 MOA at 100 yards.

I'm sure you've seen those highspeed camera video's of bullets traveling through the air. You can clearly see the bullets spinning around their own axis, but there's never an additional wobble or larger arc-spin. If what you describe is true, it would be pretty easy to see.

Benchrest shooting groups at ranges past 100 yards are converted to the shooting standard MOA so their relative angular measurements can be fairly compared.

.3031 MOA at 200 yards equals .6062 inch. In benchrest, the original standard of 1 MOA is exactly 1 inch at 100 yards is used. Same as the USA National Shooting Sports standard. There's not enough paper and pencil lead on earth to list the exact trigonometry standard of 1.047197536428328546947470696664...... adinfinitum..... so it's simplified for ordinary human use.

Here's the best "proof" I've seen regarding positive compensation for bullet drop caused by velocity spread:

http://www.geoffrey-kolbe.com/articles/rimfire_accuracy/tuning_a_barrel.htm

Slower bullet leaving at higher LOF angle above LOS. Note that as range increases past target range, 22 rimfire groups get larger by angle:

bassjam said:

Bullets don't bend their path

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Tell that to Oliver Stone!

Jim Watson said:

Sure you do. The bullseye is bigger. NRA target scoring rings are angular. F class gets you a one MOA ten ring at all usual ranges.

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The bullseye is bigger? Hahahaha!

Well, for those of us not playing in the world of NRA scoring systems, let's say the bullseye is an American made dime coin minted in 2017. A gun/bullet combo that has trouble making hits on a dime at 100 yards (say 5 times out of 10) isn't apt to hit a dime with a higher frequency at 200 yards (6 times out of 10 or more). So in terms of actual accuracy, accuracy being to actually hit a dime, no you aren't apt to have a gun that improves with distance.

Well, while the baseline assertion is that a sleepy bullet is more accurate in terms of MOA at longer range, there have been ample brags of equal group size at "stable" distances.

I don't think most folks understand what's been proved in post #61's link and picture.

Even if the barrel was immobilized and its muzzle axis did not flex in any way while the bullet exits so the LOF angle never changes, the normal velocity spread makes the down range bullet drop spread in MOA increase with range.

For the 308 Win, a 20 fps spread causes a 1/10th MOA vertical spread at 100 yards, 2 MOA at 1000.

Some folks believe the barrel is motionless (no whip, wiggle nor back thrust) while the bullet goes through it. How many of them are chiming in on this thread?

Bart B. said:

Benchrest shooting groups at ranges past 100 yards are converted to the shooting standard MOA so their relative angular measurements can be fairly compared.

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OOPs. my mistake.

Bart B. said:

I don't think most folks understand what's been proved in post #61's link and picture.

Even if the barrel was immobilized and its muzzle axis did not flex in any way while the bullet exits so the LOF angle never changes, the normal velocity spread makes the down range bullet drop spread in MOA increase with range.

For the 308 Win, a 20 fps spread causes a 1/10th MOA vertical spread at 100 yards, 2 MOA at 1000.

Some folks believe the barrel is motionless (no whip, wiggle nor back thrust) while the bullet goes through it. How many of them are chiming in on this thread?

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I agree. On a horizontal plane the two bullets at different velocities will hit the ground at the same time due to the gravity constant just at different points of impact. Without the constant of gravity a ballistics calculation is not possible and with it impact in a vertical plane can be closely estimated before the rifle is fired if velocity remains within the parameters of the calculation.

Another misconception is that bullets rise when fired then begin to fall.....well not so on a horizontal plane without lift!. Any bullet will begin to fall as soon as it is no longer supported by the barrel. This misconception could be due to the drawings on ballistics charts and such when not properly oriented with a horizontal plane.

This is proper orientation v v v v


http://www.chuckhawks.com/bullet_trajectory.htm

This is not vvvv


Say we switch things up and go Vertical! If two of the same bullets are fired vertically with different velocities, then common sense says the one with the most velocity will go higher and hit the ground later due to the factors of time and distance. Time in flight changes as trajectories go vertical and if velocities aren't the same the stall would be the factor in determining when they each hit the ground. The one that climbed higher due to higher velocity has further to fall and hits after the slower bullet. In distance the answer is the same, the faster bullet travels further.

Simply put velocity does not overcome gravity only distance on a horizontal plane!

There is a lot going on in actual ballistics not covered in sophomore physics.
Read Hatcher on vertical firing, frex.
And if you fire an actual gun dead horizontal, you are wasting ammo.

Bart B. said:

Slower bullet leaving at higher LOF angle above LOS. Note that as range increases past target range, 22 rimfire groups get larger by angle:

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Something not addressed in previous posts. Positive compensation seems not a guaranteed general advantage, it only applies where the trajectories intersect.
And I wonder, if compensation launches the low velocity round at a higher elevation to hit the same POI as the high velocity round at lower elevation, as shown in the graph, that is well and good for the high and low. But how do you know where the intermediate velocity rounds go? Does your tuner automatically put the medium velocity round in a medium trajectory straight at the same POI? It must work else the BR50 guys would not be so strong on them.

Bart B., Yesterday at 8:32 PM
"Vibrations of Rifle Barrels. Mallock, A Proceedings of the Royal Society of London (1854-1905). 1901-01-01. 68:327–344"

Is not about calling coyotes.

Both links are real; not theories. I understand why some don't believe either.

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Barrel vibrations have nothing to to with smaller groups at longer distances in a particular rifle.
You're talking about something totally different.

I clicked your "Varmint Al" link and got a page about calling Coyotes.
That's even less relevant to the actual topic.

People don't believe it because no one can prove it by demonstrating the phenomenon in real life.

Oh dear....

Yes, it is very puzzling but it is theoretically possible for bullets to produce smaller MOA groups at 2-300 yards than at 100. I didn't read all of Bart B's posts carefully, but I think he has it about right.

Someone made the comment that the tip of the bullet traces out circles as the bullet travels. That is correct. Further, the drag vector on the bullet always points directly from nose to center of base. So when the nose points toward 3:00, the drag vector still points mostly backward, but also a little toward 9:00. This will pull the bullet toward 9:00. 180 degrees later, when the bullet nose points to 9:00, the opposite happens and the bullet is pulled in the other direction. That is the source of the "restoring force".

The effect is fairly small. You probably won't detect it with your favorite SKS. But, yes, the bullet does move up, right, down, left, and up again. This effect diminishes as the bullet gets farther from the rifle. The force is a product of fluid dynamics, and would not happen in a vacuum.

Note that wind drift is NOT a product of the wind blowing against the side of the bullet, at least not mostly from that. Wind drift happens because the bullet noses slightly into the wind to keep the drag vector running from nose to center of base. The horizontal component of that drag vector is almost entirely what moves the bullet in the direction the wind is blowing. Bullets with higher BCs have smaller drag vectors, and that is why they are less affected by the wind.

bassjam said:

I don't think a top spinning on a table in a 2D world, with no momentum along the Z axis, translates to a bullet moving through a 3D world where it does have momentum along that 3rd axis. Either way, a top spinning like you describe doesn't go in a circular path wider than it's own diameter. So a .30 cal bullet under the same affect would only force a change of roughly 0.3 MOA at 100 yards.

I'm sure you've seen those highspeed camera video's of bullets traveling through the air. You can clearly see the bullets spinning around their own axis, but there's never an additional wobble or larger arc-spin. If what you describe is true, it would be pretty easy to see.

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The opposing forces of gravity and table surface don't differ from those of bullet velocity (momentum) and decelerating force (wind resistance). Until the top stabilizes the circular path can easily be several multiples of its diameter, caused by destabilizing forces of its "launch". I have yet to come across high speed footage of an unstable bullet in flight shot from the barrel axis, so if you have any pointers to such footage or another, more plausible theory that can explain this POI/distance phenomenon, please share them with us for review.

The top doesn't tend to come back to its starting place, either.

Snyper said:

Barrel vibrations have nothing to to with smaller groups at longer distances in a particular rifle.
You're talking about something totally different.

I clicked your "Varmint Al" link and got a page about calling Coyotes.

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Esten's Rifle & Tuner - on http://www.varmintal.com/aeste.htm

That's the applicable page link on Varmint Al's web site as are others next to it.

I probably understand why you think barrel vibrations have nothing to do with smaller groups at longer distances in a particular rifle. Lots of people think the same. All bullets do not leave ar exactly the same LOF angle relative to the LOS angle.

denton said:

Note that wind drift is NOT a product of the wind blowing against the side of the bullet, at least not mostly from that.

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Then please explain why round cannon balls drift with wind even though they may be spinning on some axis other than that of their trajectory. Or golf, base, ping pong, basket, bearing or croquet balls, for that matter, when propelled into moving air. They all get sucked into the lower air pressure side. Same as wings on airplanes.

If the bullet's spin is so critical to wind drift, why is rifling twist not an input to all ballistic software calulating wind drift with the bullet's rpm rate? It slows down much less than velocity does.

Anyone ever calculate the speed bullets move at right angles to the line of sight and compare a given bullet at different velocities it has at different down range points? I'm putting a spreadsheet together as an example; a Sierra 30 caliber 180-gr SBT leaving 2600 fps to 1000 yards.