I understand what people mean by it I just dont get the logic behind it. Can anyone explain what this is and if it actually plays a big role in your shot?
Advanced Marksmanship Bullets "going to sleep."
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Re: Bullets "going to sleep."
[youtube video]
I could not find it, but I'll take a stab at it since no one else has.
Remember we talk about accuracy in an angle, or arc. I prefer in my mind to envision a cone, it's 1 caliber at the muzzle, ____ (enter in your group size @ 100), and continually grows from there.
When a bullet exits the muzzle, it's not stable. It's yawing or that is to say the meplat (point) if it were a fine point pen would not be making a spot, on theoretical paper rather it would be drawing at first a surprisingly large circle, but the circle would be getting smaller and smaller as the bullet is in the process of stabilizing until eventually it is stable and it's assumed here for illustration fine point pen tip would be making a perfect little spot. And the general consensus is that the sexier the bullet profile, the further it travels down range before it's stable or "Gone to sleep." * The longer the bullet overall length, the faster twist the rifling must be and the long it takes the bullet to settle in.
Therefore, as this bullet is wobbling down range and not stable for a ways it is all the more influenced by drafts & gusts, and just typically doesn't fly a 100% reproducible course.
But why do long sexy sleek bullet's win out over short stubby chunky manly bullet's at long range even though they do not stabilize nearly as fast?
TOF, mostly, but some other factors too. [Time of flight.] A girl bullet has less drag acting upon it, so it retains it's velocity longer. This gives the environment less time to act upon it, and with the environment being the jealous Ex it is, it loves to pull the bullet as far away from the line of sight that it can, and our line of sight happens to be dead center of the target.
So. Yes, short fat stumpy linebacker looking bullets stabilize near the muzzle and make pretty little holes in the target at short range. They will shoot the pretty little boat tail off lean & long sexy girl bullets at short range any day.
But they being less aerodynamic slow faster and hence are in the environment longer, vastly longer than girl bullets. So they get pushed around more by wind/gusts/drafts as well as get drug down longer by gravity, and they run out of gas far quicker to to the point they start tumbling, that is flip end over end in flight which is really hard on accuracy.
So while linebacker bullets have a much tighter "cone of dispersion" short range, it's an hourglass shape of performance. Chunky bullets win in the accuracy department inside somewhere about the 300 meter mark, where Long super sexy girl bullets have got the kinks worked out are warmed up and settled in for the long haul just before that.
You know, it's the age old story of the bullet sexes. Man bullets are ready for action NOW, come out of the chute at 100% performance and about as quick as they are started they are almost as quick shot their wad.
But Long sexy girl bullets take a lot longer to get warmed up & performing, but once their there, they cruise along doing it exactly right for the long haul like a champ!
Understand?
[youtube video]
I could not find it, but I'll take a stab at it since no one else has.
Remember we talk about accuracy in an angle, or arc. I prefer in my mind to envision a cone, it's 1 caliber at the muzzle, ____ (enter in your group size @ 100), and continually grows from there.
When a bullet exits the muzzle, it's not stable. It's yawing or that is to say the meplat (point) if it were a fine point pen would not be making a spot, on theoretical paper rather it would be drawing at first a surprisingly large circle, but the circle would be getting smaller and smaller as the bullet is in the process of stabilizing until eventually it is stable and it's assumed here for illustration fine point pen tip would be making a perfect little spot. And the general consensus is that the sexier the bullet profile, the further it travels down range before it's stable or "Gone to sleep." * The longer the bullet overall length, the faster twist the rifling must be and the long it takes the bullet to settle in.
Therefore, as this bullet is wobbling down range and not stable for a ways it is all the more influenced by drafts & gusts, and just typically doesn't fly a 100% reproducible course.
But why do long sexy sleek bullet's win out over short stubby chunky manly bullet's at long range even though they do not stabilize nearly as fast?
TOF, mostly, but some other factors too. [Time of flight.] A girl bullet has less drag acting upon it, so it retains it's velocity longer. This gives the environment less time to act upon it, and with the environment being the jealous Ex it is, it loves to pull the bullet as far away from the line of sight that it can, and our line of sight happens to be dead center of the target.
So. Yes, short fat stumpy linebacker looking bullets stabilize near the muzzle and make pretty little holes in the target at short range. They will shoot the pretty little boat tail off lean & long sexy girl bullets at short range any day.
But they being less aerodynamic slow faster and hence are in the environment longer, vastly longer than girl bullets. So they get pushed around more by wind/gusts/drafts as well as get drug down longer by gravity, and they run out of gas far quicker to to the point they start tumbling, that is flip end over end in flight which is really hard on accuracy.
So while linebacker bullets have a much tighter "cone of dispersion" short range, it's an hourglass shape of performance. Chunky bullets win in the accuracy department inside somewhere about the 300 meter mark, where Long super sexy girl bullets have got the kinks worked out are warmed up and settled in for the long haul just before that.
You know, it's the age old story of the bullet sexes. Man bullets are ready for action NOW, come out of the chute at 100% performance and about as quick as they are started they are almost as quick shot their wad.
But Long sexy girl bullets take a lot longer to get warmed up & performing, but once their there, they cruise along doing it exactly right for the long haul like a champ!
Understand?
Re: Bullets "going to sleep."
Newb here, so pardon the over-simplification, but it also has to do with the force behind the mass and the "trauma" of leaving the muzzle: the bullet leaves the orderly, rifled environment of the barrel with its greatest kinetic energy. The result is that the bullet will destablize encountering new conditions at a time when it's also suffering greatest effects of wind friction, etc.
Ever spun a quarter on a table top by "flicking it"? At first, the quarter may buzz and arc around the table due to the shocking force you gave it from your finger. After a while it will "settle down" and the quarter will eventually "go to sleep", spinning smoothly in one spot.
The phenomenon is a practical matter in distance shooting because some rounds/set-ups will group TIGHTER are longer distances, which seems counter-intuitive.
Newb here, so pardon the over-simplification, but it also has to do with the force behind the mass and the "trauma" of leaving the muzzle: the bullet leaves the orderly, rifled environment of the barrel with its greatest kinetic energy. The result is that the bullet will destablize encountering new conditions at a time when it's also suffering greatest effects of wind friction, etc.
Ever spun a quarter on a table top by "flicking it"? At first, the quarter may buzz and arc around the table due to the shocking force you gave it from your finger. After a while it will "settle down" and the quarter will eventually "go to sleep", spinning smoothly in one spot.
The phenomenon is a practical matter in distance shooting because some rounds/set-ups will group TIGHTER are longer distances, which seems counter-intuitive.
Re: Bullets "going to sleep."
Hmm. I'd have to think about the physics of that, which is probably above my pay grade.
Something heavier, would spin slower, assuming the same flick, because it takes more energy to get it moving. As such, the dime would spin faster, but also be more suceptible to external forces.
I'm sure the ballistics and accuracy of heavier/slower bullets vs. lighter/faster bullets have been measured, I just don't have the knowledge off the top of my head...
Hmm. I'd have to think about the physics of that, which is probably above my pay grade.
Something heavier, would spin slower, assuming the same flick, because it takes more energy to get it moving. As such, the dime would spin faster, but also be more suceptible to external forces.
I'm sure the ballistics and accuracy of heavier/slower bullets vs. lighter/faster bullets have been measured, I just don't have the knowledge off the top of my head...
Re: Bullets "going to sleep."
Another thing about my analogy being rough is that flicking a coin does not benefit from channeling and rifling, as comes with a rifle barrel. The coin wouldn't move around so dramatically if the force of the flick HAD to go down a track and there was something designed to stablize the spin.
The effect of leaving the muzzle would be something akin to putting your hand out the window of a moving car. It's already going in the direction you want and you have the force to deal with wind, but you do have that moment where you need to twitch your muscles a bit to keep your hand in the same place it was before leaving due to the change of conditions.
The long and short of it is that bullet behaviour is remarkably complex and has a long list of factors beyond velocity and mass.
Another thing about my analogy being rough is that flicking a coin does not benefit from channeling and rifling, as comes with a rifle barrel. The coin wouldn't move around so dramatically if the force of the flick HAD to go down a track and there was something designed to stablize the spin.
The effect of leaving the muzzle would be something akin to putting your hand out the window of a moving car. It's already going in the direction you want and you have the force to deal with wind, but you do have that moment where you need to twitch your muscles a bit to keep your hand in the same place it was before leaving due to the change of conditions.
The long and short of it is that bullet behaviour is remarkably complex and has a long list of factors beyond velocity and mass.
Re: Bullets "going to sleep."
OK. You caught me after my coffee...
Here are a couple of graphics to further illustrate what's been said above by me and others.
First, is "Yaw", the tendancy of the bullet to be leave the muzzle at a random angle at the moment of exit. Over time, the bullet will even out, but at the very first moment, there's no telling where you are.
Here's a graphic that shows the effect of Yaw:
Over time, the bullet's spin axis and line of flight will align. This is called "dynamic stability". But again, it takes time.
Second, this effect gets married to rotational or "gyroscopic stability". GS is said to be true if the bullet's rotation around the axis exactly balances the linear force placed upon it by wind and air friction.
The preponderance of loads will be "over stable" at the time they leave the muzzle. This is because the effects of under stability is so dramatic, you want to give it MORE at the time it leaves so that as force bleeds off, it reaches the optimal.
Over stable bullets will react more randomly, and be subject to all kinds of destabilizing results. Think of the vibration that comes from an engine that's being over-reved.
Putting DS with GS on a graph will yield results that are shown conceptually in this graphic:
In this case, one axis in GS and the other is DS and their combination leads to an optimal stability during flight. At the start of the flight, the bullet's location is hard to predict, as is also true at the end of the flight. Along the way, things align and the flight is very predictable. Hence the phenomenon of tighter (more predictable) groups at 200yds than, say 100yds (in some set-ups).
If you're really into the physics, you can read to your heart's content here:
http://www.snipersparadise.com/wound/formulas.htm
OK. You caught me after my coffee...
Here are a couple of graphics to further illustrate what's been said above by me and others.
First, is "Yaw", the tendancy of the bullet to be leave the muzzle at a random angle at the moment of exit. Over time, the bullet will even out, but at the very first moment, there's no telling where you are.
Here's a graphic that shows the effect of Yaw:
Over time, the bullet's spin axis and line of flight will align. This is called "dynamic stability". But again, it takes time.
Second, this effect gets married to rotational or "gyroscopic stability". GS is said to be true if the bullet's rotation around the axis exactly balances the linear force placed upon it by wind and air friction.
The preponderance of loads will be "over stable" at the time they leave the muzzle. This is because the effects of under stability is so dramatic, you want to give it MORE at the time it leaves so that as force bleeds off, it reaches the optimal.
Over stable bullets will react more randomly, and be subject to all kinds of destabilizing results. Think of the vibration that comes from an engine that's being over-reved.
Putting DS with GS on a graph will yield results that are shown conceptually in this graphic:
In this case, one axis in GS and the other is DS and their combination leads to an optimal stability during flight. At the start of the flight, the bullet's location is hard to predict, as is also true at the end of the flight. Along the way, things align and the flight is very predictable. Hence the phenomenon of tighter (more predictable) groups at 200yds than, say 100yds (in some set-ups).
If you're really into the physics, you can read to your heart's content here:
http://www.snipersparadise.com/wound/formulas.htm
Re: Bullets "going to sleep."
http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=918725
I think this is the video referenced above. It is interesting.
EL
http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=918725
I think this is the video referenced above. It is interesting.
EL
Re: Bullets "going to sleep."
had an argument on here about this very thing and how a bullet will "settle down" or "go to sleep" at range and that it can get more accurate at distance. The argument was that bullets don't go to sleep. I have the vid but I see you already got it posted
had an argument on here about this very thing and how a bullet will "settle down" or "go to sleep" at range and that it can get more accurate at distance. The argument was that bullets don't go to sleep. I have the vid but I see you already got it posted
Re: Bullets "going to sleep."
To add to this "more accurate at distance":
Bullets will go to sleep and get more accurate as long as the measurement is in moa. You will not have smaller groups at distance in inches. A shot cone will always be a cone.
To add to this "more accurate at distance":
Bullets will go to sleep and get more accurate as long as the measurement is in moa. You will not have smaller groups at distance in inches. A shot cone will always be a cone.
Re: Bullets "going to sleep."
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Austan</div><div class="ubbcode-body">To add to this "more accurate at distance":
Bullets will go to sleep and get more accurate as long as the measurement is in moa. You will not have smaller groups at distance in inches. A shot cone will always be a cone.
</div></div>
Right. Should have been more clear. Hard to digest it all in a quick post.
Further to the point, this stuff really only matters for someone aspiring to premier competition. I don't compete; I just want to know I can get a bullet on a target. The physics is just an academic curiosity.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Austan</div><div class="ubbcode-body">To add to this "more accurate at distance":
Bullets will go to sleep and get more accurate as long as the measurement is in moa. You will not have smaller groups at distance in inches. A shot cone will always be a cone.
</div></div>
Right. Should have been more clear. Hard to digest it all in a quick post.
Further to the point, this stuff really only matters for someone aspiring to premier competition. I don't compete; I just want to know I can get a bullet on a target. The physics is just an academic curiosity.
Re: Bullets "going to sleep."
well that explains why my groups at 100yd are mediocre while my 300yd groups are exceptional.
well that explains why my groups at 100yd are mediocre while my 300yd groups are exceptional.
Re: Bullets "going to sleep."
So do you sleep with female bullets or male bullets?
So do you sleep with female bullets or male bullets?
Re: Bullets "going to sleep."
I work up at 200 just because I can't at 300. Most of the time.
I work up at 200 just because I can't at 300. Most of the time.
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