Jim Watson
Member
I understand the process of "compensation" going back to the .303 and the smallbore tuners certainly have their followers.
What about spread in directions other than vertical?
What about spread in directions other than vertical?
Is it possible for a rifle to be more accurate at distance than 100 yards?
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wally
Member
The size of independently shot groups at various distances can't verify the claim. Too many other factors can make a given group larger or smaller.
The Litz challenge measures the size of the groups as the same bullets fly through 100 yards and a longer range. The two groups at various distances are made from the same shots. Details are on his website.
The Litz challenge measures the size of the groups as the same bullets fly through 100 yards and a longer range. The two groups at various distances are made from the same shots. Details are on his website.
imashooter
Member
Back to the opening question; "Is it possible for a rifle to be more accurate at distance than 100 yards?"
Yes, it is possible.
Yes, it is possible.
cdb1
Member
As I stated before I've never seen it but in theory I guess it is possible.
If the barrel and bullet are in harmonious accord at the exact moment the bullet leaves the barrel, then the bullet should exhibit the same accuracy at all distances. If on the other hand the bullet is on a yin axis and the barrel is on a yang axis at exact moment of departure, but are heading back towards each other then accuracy shall improve as distance increases. If one is on a yin axis, the other yang but are on different tangents at time of departure then accuracy decreases progressively. If something happens to disrupt the time space continuum, such as an electricity fart at the time the trigger is pulled then the outcome cannot be predicted with any probability. I can't explain it any simpler.
If the barrel and bullet are in harmonious accord at the exact moment the bullet leaves the barrel, then the bullet should exhibit the same accuracy at all distances. If on the other hand the bullet is on a yin axis and the barrel is on a yang axis at exact moment of departure, but are heading back towards each other then accuracy shall improve as distance increases. If one is on a yin axis, the other yang but are on different tangents at time of departure then accuracy decreases progressively. If something happens to disrupt the time space continuum, such as an electricity fart at the time the trigger is pulled then the outcome cannot be predicted with any probability. I can't explain it any simpler.
bassjam
Member
You guys are killing me, is this a serious debate?? Assuming bullets do need to stabilize, if a bullet is not stabilized at 100 yards, and is shooting at, lets say 1 MOA, it's not suddenly going to change it's path once it stabilizes and re-zero towards 0.75 MOA at 200 yards! Even if the bullet does stabilize at greater distances, the best it can ever do is follow that initial path of 1 MOA.
I illustrated what some of you are saying would happen in a CAD drawing (not to scale), and also illustrated what really happens.
This isn't a physics question, that much is obvious to me. This is a psychological question for those who concentrate better when shooting at further distances. If physics is involved, it's with the optic and not the firearm/bullet.
I illustrated what some of you are saying would happen in a CAD drawing (not to scale), and also illustrated what really happens.
This isn't a physics question, that much is obvious to me. This is a psychological question for those who concentrate better when shooting at further distances. If physics is involved, it's with the optic and not the firearm/bullet.
bassjam
Member
This is basically Newton's First Law, that an object will remain at rest, or in motion in a straight line, unless acted upon by an outside force.
Except that if they leave at different muzzle velocities at the same angle above the LOS, there's different drop at longer ranges. 308 Win bullets have about a 2/10ths inch/moa vertical spread or drop difference at 100 yards with a 100 fps spread in muzzle velocity. At 1000 yards, there's about a 40 inch (4 MOA) difference in drop for that same velocity spread. This is why mid range groups will be the biggest when there's positive compensation for bullet drop as bullets leave on the muzzle axis up swing making long range groups smaller.
A small spread in BC bullets have will cause more drop per range band further down range.
Wind drifts bullets further the last hundred yards of range for a given cross wind than in the first hundred yards of range. And winds the first third of range have a greater effect on drift on target than the last third.
Subtle cross winds are the main cause of horizontal changes to bullets trajectory.
There's evidence that bullets passing a few thousandths inch from a down range item will deflect a tiny bit away from it cause by its shock wave disrupting its flight as it bounces off that object.
That 1 to 2 percent spread of bullet BC caused by their microscopic unbalanced condition will cause a slight change in wind drift per mph of air blowing on the bullet.
If you've ever observed a spinning top, you know that state of stabilization is an analogue function, not just 0 or 1. A spinning bullet follows the flight path surprisingly loosely, as a function of its rotational vs. linear speed. A projectile shot from a non-rifled barrel would be a much simpler case to model. Thirtysomething years ago (when schools weren't as PC or hysterical about this as they are now) I did a fairly extensive study and presentation of factors affecting the flight path of a bullet and while I can't remember the details anymore, varying state of stabilization and its effect on variation on the flight path is an actual phenomenon. In some (rare?) cases it can manifest itself by a relatively smaller grouping angle at greater distances.
bassjam
Member
As I showed in the first illustration, IF bullet groups could possibly get smaller, at some point their vectors would cross paths and you'd end up with larger groups again. Regardless, this kind of breaks Newton's law, as the stabilized bullet can lesson those outside forces that change direction, but it certainly can't reverse it! You guys are acting like bullets have some sort of internal tracking device and can change the flight path towards some magical beacon on the target at longer distances.
"Stabilized" is a constantly changing variable as a function of rotation and velocity, not an on-off toggle. In this case it doesn't break any of the Newton's laws any more than a spinning top does, varying its wobble axis from rotational to static and back. Median flight path isn't altered, the deviation of a bullet's actual location within a timeframe in Y and Z axis (given that the direction of travel is X) from it can be. This is the plausible explanation of observed and repeatable relative accuracy improvement when the distance is increased. It doesn't necessarily have to be attributed to shoddy shooting, chance, insufficient sample size or other subjective factor. This is something that can and occasionally does occur with bench-mounted rail guns too.
bassjam
Member
A deviation on an Y/Z plane will change it's flight path. Bullets don't bend their path, they move in straight line until gravity, wind, or something solid deflects it's path.
Jim Watson
Member
But what about your buds at Sierra with their tunnel?
I admired Sir Joseph Whitworth. When he wanted to improve the Empire's rifles, he built a 500 yard enclosed range. Two of them, the first burned down.
Carl N. Brown
Member
I have heard a similar argument to that presented in Bryan Litz, "Epicylcic Swerve", Applied Ballistics. "In other words, a rifle that groups 1” at 100 yards grouping 1.5” at 200 yards (you would expect no less than 2” at 200 yards)."
It's theoretical, sounds plausible. I recall observing a similar effect years ago shooting my son's .308 during load development with boattail bullets at 50 yds, 100 yds and 200 yds. Past 200 yards, groups seemed to open up proportional to the 200 yd group size not proportional to the 100 yard group size. (I think we should have tweaked the load for 200 yard group size, not 100 yard size.)
What I was told was, with boattail bullets at certain velocities, until the bullet aerodynamically stabilizes, it wobbles more around the center line of the trajectory and as the bullet slows down it becomes more stable and wobbles less around the centerline of the trajectory. You could have a gun that shoots 1" groups at 100 yards (1 MOA), then 1.5" groups at 200 yards (0.75 MOA), 2.5" groups at 300 yards (0.83 MOA), and finally opening up past 1 MOA again as air effects, defects in bullet center of gravity, etc. degrade the grouping.
Practically, in the field, subject to muscle tremor, variations in wind across the field, etc., am I going to notice 1 MOA at 100 yd, 0.75 MOA at 200yd, 0.8+ MOA at 300 yd, 1 MOA at 350 yd, slightly over 1 MOA at 400 yd at a club range? Maybe, probably not. (On the family property on the mountain, second growth timber, finding 65 yds clear to shoot is a problem, so this is all theoretical and not practical to me.)
It's theoretical, sounds plausible. I recall observing a similar effect years ago shooting my son's .308 during load development with boattail bullets at 50 yds, 100 yds and 200 yds. Past 200 yards, groups seemed to open up proportional to the 200 yd group size not proportional to the 100 yard group size. (I think we should have tweaked the load for 200 yard group size, not 100 yard size.)
What I was told was, with boattail bullets at certain velocities, until the bullet aerodynamically stabilizes, it wobbles more around the center line of the trajectory and as the bullet slows down it becomes more stable and wobbles less around the centerline of the trajectory. You could have a gun that shoots 1" groups at 100 yards (1 MOA), then 1.5" groups at 200 yards (0.75 MOA), 2.5" groups at 300 yards (0.83 MOA), and finally opening up past 1 MOA again as air effects, defects in bullet center of gravity, etc. degrade the grouping.
Practically, in the field, subject to muscle tremor, variations in wind across the field, etc., am I going to notice 1 MOA at 100 yd, 0.75 MOA at 200yd, 0.8+ MOA at 300 yd, 1 MOA at 350 yd, slightly over 1 MOA at 400 yd at a club range? Maybe, probably not. (On the family property on the mountain, second growth timber, finding 65 yds clear to shoot is a problem, so this is all theoretical and not practical to me.)
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Sunray
Member
No amount of wishful thinking will alter the fact that a bullet is not going to arc back in past 100 without input from something. Think in terms of an ellipse like the arc of trajectory on its side. Doesn't happen. Physics doesn't allow it.
"...boattail bullet begins to stabilize at around 150 yards..." It takes approximately 300 yards for a .30 calibre bullet to stabilize. A .308" bullet out of either a .30-06 or .308 doesn't penetrate as well at 150 as it does past 300 yards.
However, group size at distance isn't as important as how consistently the rifle will do it.
"...boattail bullet begins to stabilize at around 150 yards..." It takes approximately 300 yards for a .30 calibre bullet to stabilize. A .308" bullet out of either a .30-06 or .308 doesn't penetrate as well at 150 as it does past 300 yards.
However, group size at distance isn't as important as how consistently the rifle will do it.
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?
In observing benchrest groups shot by the same rifle through 300 yards, they typically grow about 5 to 10 percent in size per hundred yards of range through 300. Those bullets must be well stabilized by 100 yards to do that. They're shot at optimum twist rates for the velocities cartridges shoot them.
I've seen Sierra's 100-yard test targets with 10 shot groups on each in the ones and low twos. They tried 200 yard testing in their California plant to see if groups might show bullets stabilized more over the second 100 yards but saw no evidence of it happening; they stayed at 100 yards. While the tiny unbalance most bullets have tends to corkscrew their trajectory for several yards past the muzzle, they soon stabilize then take the path they're on when that happens.
I've seen Sierra's 100-yard test targets with 10 shot groups on each in the ones and low twos. They tried 200 yard testing in their California plant to see if groups might show bullets stabilized more over the second 100 yards but saw no evidence of it happening; they stayed at 100 yards. While the tiny unbalance most bullets have tends to corkscrew their trajectory for several yards past the muzzle, they soon stabilize then take the path they're on when that happens.
Don't forget the slight horizontal trajectory caused by spin drift. And the coriolis effect due to earth's rotation horizontally; tiny with rifle bullets, bigger with large military projectiles. And the etovos effect causing vertical spread.
These are all fixed for a given location and direction of fire; they're constants then. Someplace else, they'll change a smidgen.
Jim Watson
Member
wally
Member
Brian Litz has put his money where his mouth is and says its not going to happen. If you can go to his range/lab and demonstrate it with your rifle and ammo he'll reimburse all your expenses, otherwise its on your dime. He is confident in the physics, but wanting to learn if his physics is somehow wrong (unlikely).
Internet hand-waving arguments for or against aside, a challenge is on the table for anyone who can actually demonstrate it happening.
Internet hand-waving arguments for or against aside, a challenge is on the table for anyone who can actually demonstrate it happening.
cdb1
Member
Uhhh..... I was making everything up as I went along.
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Jim Watson
Member
I am sure that if somebody takes Mr Litz up on his test challenge, they will find a way to crawfish.
I can think of excuses:
His physical intermediate target disturbed the flight of the bullet.
His far target was not far enough away.
I can think of excuses:
His physical intermediate target disturbed the flight of the bullet.
His far target was not far enough away.
Wreck-n-Crew
Member
B happens more often than A I would guess.
Hanzo581
Member
Yeah, this is basically the visual version of what I posted. They are digging way too deep into something that fundamentally is impossible.
It can most certainly happen, however trying to explain it in terms of classical Neutonian physics is nearly impossible. There is a weak magneto effect of the spinning lead core setting up a Meissner effect as the projectile cuts lines of magnetic flux, of course this will be more pronounced on east-west trajectories. In any event, this impacts the Heisenberg uncertainty greatly until enough energy is lost within the system and the projectile's Fourier transform approaches zero. Now, if you buy any of this, I'd like to talk to you about some amazing oceanfront real estate opportunities in Arizona
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