Jerry Tracy
New member
Just curious how many times a bullet spins within a 100 yard span. I'm sure this will depend and or vary with different twist rates but just a ballpark number will do.
Bullet revolutions per 100 yards
- Thread starter Jerry Tracy
- Start date
CrazyHorse66
Active member
36 inches in a yard.
1-9" twist= 4 revolutions per yard
400 revolutions per 100 yards.
1-9" twist= 4 revolutions per yard
400 revolutions per 100 yards.
CrazyHorse66
Active member
300 revolutions for 1-12"...
Jerry Tracy
New member
I'm assuming that the bullet will lost its spin rate just as it looses its velocity?
CrazyHorse66
Active member
Originally Posted By: Jerry TracyI'm assuming that the bullet will lost its spin rate just as it looses its velocity?
Absolutely....
ETA: Not at the same proportional rate though...
Paging CatShooter...
Absolutely....
ETA: Not at the same proportional rate though...
Paging CatShooter...
CrazyHorse66
Active member
Interesting....
Here's the true formula for RPM:
Bullet RPM = MV X 720/Twist Rate (in inches)
According to this site...
Here's the true formula for RPM:
Bullet RPM = MV X 720/Twist Rate (in inches)
According to this site...
CatShooter
New member
Originally Posted By: Jerry TracyI'm assuming that the bullet will lost its spin rate just as it looses its velocity?
It does not - it looses forwards velocity much faster than the spin rate - so in 100 yds, it spins more than the formula suggests.
.
It does not - it looses forwards velocity much faster than the spin rate - so in 100 yds, it spins more than the formula suggests.
.
Smokeless
New member
Originally Posted By: CatShooterOriginally Posted By: Jerry TracyI'm assuming that the bullet will lost its spin rate just as it looses its velocity?
It does not - it looses forwards velocity much faster than the spin rate - so in 100 yds, it spins more than the formula suggests.
.
This ratio is why, if properly stabilized at the muzzle, a bullet will become more stable down range gyroscopically. Sometimes with very long bullets that require a lot of stabilization, accuracy at 200yds is better than it is at 100yds.
It does not - it looses forwards velocity much faster than the spin rate - so in 100 yds, it spins more than the formula suggests.
.
This ratio is why, if properly stabilized at the muzzle, a bullet will become more stable down range gyroscopically. Sometimes with very long bullets that require a lot of stabilization, accuracy at 200yds is better than it is at 100yds.
Jack Roberts
Moderator - Deceased
This ratio is why, if properly stabilized at the muzzle, a bullet will become more stable down range gyroscopically. Sometimes with very long bullets that require a lot of stabilization, accuracy at 200yds is better than it is at 100yds.
The better MOA accuracy usually doesn't become apparent untill 300 or better. But any bullet stable at short range will always be stable at long range.
Jack
The better MOA accuracy usually doesn't become apparent untill 300 or better. But any bullet stable at short range will always be stable at long range.
Jack
Smokeless
New member
Originally Posted By: Jack RobertsThis ratio is why, if properly stabilized at the muzzle, a bullet will become more stable down range gyroscopically. Sometimes with very long bullets that require a lot of stabilization, accuracy at 200yds is better than it is at 100yds.
The better MOA accuracy usually doesn't become apparent untill 300 or better. But any bullet stable at short range will always be stable at long range.
Jack
More stable. As forward velocity decreases, the gyroscoptic spin decreases much less. Since spin equals stability, the bullet becomes more stable the farther down range it goes.
Weather or not you can see it as soon as 200yds is in the eye of the shooter, but yes, it is more evident in terms of MOA farther down range.
The better MOA accuracy usually doesn't become apparent untill 300 or better. But any bullet stable at short range will always be stable at long range.
Jack
More stable. As forward velocity decreases, the gyroscoptic spin decreases much less. Since spin equals stability, the bullet becomes more stable the farther down range it goes.
Weather or not you can see it as soon as 200yds is in the eye of the shooter, but yes, it is more evident in terms of MOA farther down range.
CatShooter
New member
Originally Posted By: SmokelessOriginally Posted By: CatShooterOriginally Posted By: Jerry TracyI'm assuming that the bullet will lost its spin rate just as it looses its velocity?
It does not - it looses forwards velocity much faster than the spin rate - so in 100 yds, it spins more than the formula suggests.
.
This ratio is why, if properly stabilized at the muzzle, a bullet will become more stable down range gyroscopically. Sometimes with very long bullets that require a lot of stabilization, accuracy at 200yds is better than it is at 100yds.
Not true, and not related at all.
1 - If a bullet starts out unstable, it will never be stable. Pesky laws of physics.
2 - A bullet that is not accurate at 100 yards, cannot be accurate at a further distance - to do so, it would presuppose that the bullet was intelligent. First, it would know that it was off track at 100 yards. Then it would know which direction to turn and correct (in a world that is spinning at 250,000+ rpm), could intelligently change it's direction to correct, and then know when it was back on track, and do a second path correction to go straight ahead.
It is not physically possible.
When your groups are smaller down range (in size OR m.o.a.) you have a parallax problem.
It does not - it looses forwards velocity much faster than the spin rate - so in 100 yds, it spins more than the formula suggests.
.
This ratio is why, if properly stabilized at the muzzle, a bullet will become more stable down range gyroscopically. Sometimes with very long bullets that require a lot of stabilization, accuracy at 200yds is better than it is at 100yds.
Not true, and not related at all.
1 - If a bullet starts out unstable, it will never be stable. Pesky laws of physics.
2 - A bullet that is not accurate at 100 yards, cannot be accurate at a further distance - to do so, it would presuppose that the bullet was intelligent. First, it would know that it was off track at 100 yards. Then it would know which direction to turn and correct (in a world that is spinning at 250,000+ rpm), could intelligently change it's direction to correct, and then know when it was back on track, and do a second path correction to go straight ahead.
It is not physically possible.
When your groups are smaller down range (in size OR m.o.a.) you have a parallax problem.
Jabey9210
Member
i tried to quote but messed it up!!!!
++++++1 Cat A lot of people believe especially with berger and other VLD's that it takes time for them to stabilize. There is no way any bullet is more accurate down range than at the muzzle especially due to wind, pressure, coriolis and other atmoshperic conditions. If people are more accurate at 200 yards than they are at 100 yards they should try to turn there magnification down at 100 yrds if they have a 20 power scope turned all the way up at 200 yards if they shoot at 100 yards with it turned down to 10 power they will find their groups will shrink up. I don't know how to explain it in words but try it it really does work and if the bullet is spinning 1 rev per 9 inches it will continue to spin once every 9 inches until it hits the target or the ground yes the revolution slows down but so does the velocity even though it takes the bullet longer in time to rotate it also takes it longer in time to travel the 9 inches and will continue to rotate once every nine inches.
++++++1 Cat A lot of people believe especially with berger and other VLD's that it takes time for them to stabilize. There is no way any bullet is more accurate down range than at the muzzle especially due to wind, pressure, coriolis and other atmoshperic conditions. If people are more accurate at 200 yards than they are at 100 yards they should try to turn there magnification down at 100 yrds if they have a 20 power scope turned all the way up at 200 yards if they shoot at 100 yards with it turned down to 10 power they will find their groups will shrink up. I don't know how to explain it in words but try it it really does work and if the bullet is spinning 1 rev per 9 inches it will continue to spin once every 9 inches until it hits the target or the ground yes the revolution slows down but so does the velocity even though it takes the bullet longer in time to rotate it also takes it longer in time to travel the 9 inches and will continue to rotate once every nine inches.
Last edited:
CatShooter
New member
Originally Posted By: Jabey9210i tried to quote but messed it up!!!!
++++++1 Cat A lot of people believe especially with berger and other VLD's that it takes time for them to stabilize. There is no way any bullet is more accurate down range than at the muzzle especially due to wind, pressure, coriolis and other atmoshperic conditions. If people are more accurate at 200 yards than they are at 100 yards they should try to turn there magnification down at 100 yrds if they have a 20 power scope turned all the way up at 200 yards if they shoot at 100 yards with it turned down to 10 power they will find their groups will shrink up. I don't know how to explain it in words but try it it really does work and if the bullet is spinning 1 rev per 9 inches it will continue to spin once every 9 inches until it hits the target or the ground yes the revolution slows down but so does the velocity even though it takes the bullet longer in time to rotate it also takes it longer in time to travel the 9 inches and will continue to rotate once every nine inches.
Jabey. To quote a post, just klicky on the "Quote" button, next to the reply button (it is the second one from the left, under the post you want to quote. then ad your text where ever you want.
You can preview your post by hitting the "preview post" button - you will see what your post will look like - it appears below the box you are typing in.
The garbage that people believe just astonishes me. But they read it and believe it, without asking the author to explain (in real words) what they are saying.
People read garbage that makes no sense and just believe it without thinking about it.
And some of this stuff is so off the wall, that if you stop and think about the logic of it for 5 minutes, you double up laughing.
---
The bullet looses velocity fairly fast at first - as it slows down, it looses velocity at a slower rate, until it reaches a point where it is "almost" not loosing velocity, and it crashes into the ground (and then looses all of it's velocity at once).
The rotational spin does NOT decrease at the same rate, because the rotational drag is non-existant in the early stages of flight, which is exactly when the forward drag is highest.
Far down range (very far), the forward drag is much less, but because the bullet is now falling sideways, AND the air flow over the body now involves the rifling groves (which it does not in the early phases of flight), the rotational drag increases. So the rotational decrease is NEVER in sync with the forwards decrease in velocity.
Never ever.
A bullet that is shot from a 9" twist... has it's forward and rotational velocities out of sync within feet of the muzzle.
++++++1 Cat A lot of people believe especially with berger and other VLD's that it takes time for them to stabilize. There is no way any bullet is more accurate down range than at the muzzle especially due to wind, pressure, coriolis and other atmoshperic conditions. If people are more accurate at 200 yards than they are at 100 yards they should try to turn there magnification down at 100 yrds if they have a 20 power scope turned all the way up at 200 yards if they shoot at 100 yards with it turned down to 10 power they will find their groups will shrink up. I don't know how to explain it in words but try it it really does work and if the bullet is spinning 1 rev per 9 inches it will continue to spin once every 9 inches until it hits the target or the ground yes the revolution slows down but so does the velocity even though it takes the bullet longer in time to rotate it also takes it longer in time to travel the 9 inches and will continue to rotate once every nine inches.
Jabey. To quote a post, just klicky on the "Quote" button, next to the reply button (it is the second one from the left, under the post you want to quote. then ad your text where ever you want.
You can preview your post by hitting the "preview post" button - you will see what your post will look like - it appears below the box you are typing in.
The garbage that people believe just astonishes me. But they read it and believe it, without asking the author to explain (in real words) what they are saying.
People read garbage that makes no sense and just believe it without thinking about it.
And some of this stuff is so off the wall, that if you stop and think about the logic of it for 5 minutes, you double up laughing.
---
The bullet looses velocity fairly fast at first - as it slows down, it looses velocity at a slower rate, until it reaches a point where it is "almost" not loosing velocity, and it crashes into the ground (and then looses all of it's velocity at once).
The rotational spin does NOT decrease at the same rate, because the rotational drag is non-existant in the early stages of flight, which is exactly when the forward drag is highest.
Far down range (very far), the forward drag is much less, but because the bullet is now falling sideways, AND the air flow over the body now involves the rifling groves (which it does not in the early phases of flight), the rotational drag increases. So the rotational decrease is NEVER in sync with the forwards decrease in velocity.
Never ever.
A bullet that is shot from a 9" twist... has it's forward and rotational velocities out of sync within feet of the muzzle.
CrazyHorse66
Active member
This is why PM pays CatShooter the big bucks to hang out here.
JerrySchmitt
New member
Originally Posted By: Jabey9210i tried to quote but messed it up!!!!
++++++1 Cat A lot of people believe especially with berger and other VLD's that it takes time for them to stabilize. There is no way any bullet is more accurate down range than at the muzzle especially due to wind, pressure, coriolis and other atmoshperic conditions. If people are more accurate at 200 yards than they are at 100 yards they should try to turn there magnification down at 100 yrds if they have a 20 power scope turned all the way up at 200 yards if they shoot at 100 yards with it turned down to 10 power they will find their groups will shrink up. I don't know how to explain it in words but try it it really does work and if the bullet is spinning 1 rev per 9 inches it will continue to spin once every 9 inches until it hits the target or the ground yes the revolution slows down but so does the velocity even though it takes the bullet longer in time to rotate it also takes it longer in time to travel the 9 inches and will continue to rotate once every nine inches.
Turning down the power of the scope will not improve your accuracy unless there is something very wrong with your scope or your technique.
++++++1 Cat A lot of people believe especially with berger and other VLD's that it takes time for them to stabilize. There is no way any bullet is more accurate down range than at the muzzle especially due to wind, pressure, coriolis and other atmoshperic conditions. If people are more accurate at 200 yards than they are at 100 yards they should try to turn there magnification down at 100 yrds if they have a 20 power scope turned all the way up at 200 yards if they shoot at 100 yards with it turned down to 10 power they will find their groups will shrink up. I don't know how to explain it in words but try it it really does work and if the bullet is spinning 1 rev per 9 inches it will continue to spin once every 9 inches until it hits the target or the ground yes the revolution slows down but so does the velocity even though it takes the bullet longer in time to rotate it also takes it longer in time to travel the 9 inches and will continue to rotate once every nine inches.
Turning down the power of the scope will not improve your accuracy unless there is something very wrong with your scope or your technique.
CatShooter
New member
Originally Posted By: JerrySchmittOriginally Posted By: Jabey9210i tried to quote but messed it up!!!!
++++++1 Cat A lot of people believe especially with berger and other VLD's that it takes time for them to stabilize. There is no way any bullet is more accurate down range than at the muzzle especially due to wind, pressure, coriolis and other atmoshperic conditions. If people are more accurate at 200 yards than they are at 100 yards they should try to turn there magnification down at 100 yrds if they have a 20 power scope turned all the way up at 200 yards if they shoot at 100 yards with it turned down to 10 power they will find their groups will shrink up. I don't know how to explain it in words but try it it really does work and if the bullet is spinning 1 rev per 9 inches it will continue to spin once every 9 inches until it hits the target or the ground yes the revolution slows down but so does the velocity even though it takes the bullet longer in time to rotate it also takes it longer in time to travel the 9 inches and will continue to rotate once every nine inches.
Turning down the power of the scope will not improve your accuracy unless there is something very wrong with your scope or your technique.
What he said!!
.
++++++1 Cat A lot of people believe especially with berger and other VLD's that it takes time for them to stabilize. There is no way any bullet is more accurate down range than at the muzzle especially due to wind, pressure, coriolis and other atmoshperic conditions. If people are more accurate at 200 yards than they are at 100 yards they should try to turn there magnification down at 100 yrds if they have a 20 power scope turned all the way up at 200 yards if they shoot at 100 yards with it turned down to 10 power they will find their groups will shrink up. I don't know how to explain it in words but try it it really does work and if the bullet is spinning 1 rev per 9 inches it will continue to spin once every 9 inches until it hits the target or the ground yes the revolution slows down but so does the velocity even though it takes the bullet longer in time to rotate it also takes it longer in time to travel the 9 inches and will continue to rotate once every nine inches.
Turning down the power of the scope will not improve your accuracy unless there is something very wrong with your scope or your technique.
What he said!!
.
CatShooter
New member
Originally Posted By: Jabey9210
"If people are more accurate at 200 yards than they are at 100 yards they should try to turn there magnification down at 100 yards if they have a 20 power scope turned all the way up at 200 yards if they shoot at 100 yards with it turned down to 10 power they will find their groups will shrink up. I don't know how to explain it in words but try it it really does work "
I'll "try", but I think it is an uphill battle.
If your scope changes group size at different powers and different ranges, then you might be a redneck - or you are suffering from the deadly curse of... Parallax.
Go here and read this (twice).
http://www.snipercountry.com/Articles/Parallax.asp
Then come back and ask questions (if you still have them).
Parallax causes bigger problems (and bigger groups) as power is increased. Most guys think they have parallax under control - they don't!
.
"If people are more accurate at 200 yards than they are at 100 yards they should try to turn there magnification down at 100 yards if they have a 20 power scope turned all the way up at 200 yards if they shoot at 100 yards with it turned down to 10 power they will find their groups will shrink up. I don't know how to explain it in words but try it it really does work "
I'll "try", but I think it is an uphill battle.
If your scope changes group size at different powers and different ranges, then you might be a redneck - or you are suffering from the deadly curse of... Parallax.
Go here and read this (twice).
http://www.snipercountry.com/Articles/Parallax.asp
Then come back and ask questions (if you still have them).
Parallax causes bigger problems (and bigger groups) as power is increased. Most guys think they have parallax under control - they don't!
.
Ridgeline17
New member
So then all along these 14x scopes we have been buyin was useless. And look at the money I could have saved.
CatShooter
New member
Originally Posted By: Ridgeline17So then all along these 14x scopes we have been buyin was useless. And look at the money I could have saved.
Yeah... send it to me. I have a 2x Weaver I will send you.
Yeah... send it to me. I have a 2x Weaver I will send you.
Ridgeline17
New member
You still owe me a Stevens 200 and a box of crayons.
