A theoretical question. Shoot a 1" group at 50 or 100 yards. Ignore drop, the shooter and all outside influence on the boolit.
At what range does the group double in size?
I have always gone by; double the range, double the group. In other words, 1" at 50 would give 2" at 100. 1" at 100 will give 2" at 200.
Line of sight only.

Take figures out to 600 or 700 yards if you can.

I use that same general rule but Art Alphin claims that some bullets take longer than others to settle down and "go to sleep" as he puts it leading to smaller groups at longer distances than shorter. I have noticed this effect with some rifles I have owned, they would print a better group at 200 yds than at say, 100 yds.

I am not sure if it doubles between 50 and 100 yds.100 to 200yds. and beyond this holds true.At least on paper.My friend has a Rail gun where if conditions are right between 100 to 600 yds.Has less then double the size groups.It is better from 300 yds on out than between 100 to 300.It is a 338 lapau and I think he is using 300 gr. boolits.

The problem with this is you can't ignore all outside influences. There is no such thing in the real world as an exact duplication of each shot, each charge, each bullet and other components, especially from a handgun with five, six or more cylinders. Let alone wind and other atmospheric conditions, bullet weight, caliber, velocity and projectile shape.

The inside and outside influences make the spread.

With a target rifle I have seen 10 bullets leave one small hole that looked like it came from one bullet, but it still wasn't EXACTLY the size hole just one bullet would have made.

The reason I ask is that it has always baffled me how sometimes we can shoot smaller groups at long range then at close range even with revolvers that do not over spin bullets that need distance to go to "sleep."
Actual bullet flight makes my brain boil even after watching thousands through a scope. Why did I shoot center on 200 meter rams as good as on 50 meter chickens?
If I get the aiming point right for bullet drop, how can I hit a can at 200 yards just like I do at 100?
Now we have sniper rifles that you punch in figures on a little computer and can hit the first shot at 2000 yards or more.

The bullet settling down idea is best envisioned like a child's toy top spinning very fast and tracking sporatically (walking) before settling and holding one spot on the floor before time slows the rotation and the top begins to wobble and fall.

At close ranges the bullet is over stabilized due to a too fast twist rate (rpms) that actually fights the bullet off the straight line pathkind of like trying to stay on a merry-go-round that is spinning fast, or that one ride at the fair that pushes you back against the wall and make you feel heavy. As the bullet looses velocity and rpms there is less centrifugal force pulling the bullet axis off the intended travel line. This is also why at longer ranges groups open up, the bullet isn't fast enough (both velocity and rpms, more importantly rpms) to prevent yaw or keep the bullet axis on the intended travel line.


A gyroscope on a pedestal is another good visual example, it will actually lay ove some 30 degrees and track a wide circle before slowing and standing upright, once rotational force settles into the "sweet spot"


The answer to the original question varies with mass, twist rate(rpms); velocity; ballistic coefs.; drag and air viscosity (thickness, density humidity, theses are sometimes described as density altitude, where temp, pressure and humidity are combined to give a certain area/ volume of air a value for the difficulty of traveling through.) and deviations of each from shot to shot.

Having no formal long range shooting experience per se, this is a collection of ideas from some of my Physics and Statistics classes back in the day and my flight training...

Hope some of that helps, sorry for the length and jumpiness, I get excited sometimes...

quote:

Originally posted by bfrshooter:
A theoretical question. Shoot a 1" group at 50 or 100 yards. Ignore drop, the shooter and all outside influence on the boolit.
At what range does the group double in size?
I have always gone by; double the range, double the group. In other words, 1" at 50 would give 2" at 100. 1" at 100 will give 2" at 200.
Line of sight only.

If bullets shot a consistent angle this would be true, but they don't. We know this by shooting at longer distances and not seeing the doubling of group sizes. Only ones that argue that the groups douible are the ones that do not shoot at longer distances

quote:

Originally posted by bfrshooter:
The reason I ask is that it has always baffled me how sometimes we can shoot smaller groups at long range then at close range even with revolvers that do not over spin bullets that need distance to go to "sleep."
Actual bullet flight makes my brain boil even after watching thousands through a scope. Why did I shoot center on 200 meter rams as good as on 50 meter chickens?
If I get the aiming point right for bullet drop, how can I hit a can at 200 yards just like I do at 100?
Now we have sniper rifles that you punch in figures on a little computer and can hit the first shot at 2000 yards or more.

The first time I had a clue on what happens to a bullet in flight was when I started High power Shooting.As a spotter ,sitting behind the shooter you can see the bullet in flight.The more humid the better you can see.
Problem is if you depend on computers,some time its going to fail.You best know how to dope the wind and use a scope for range estimation.
I have found that when ever I think I have it all figured out something changes.

quote:

The bullet settling down idea is best envisioned like a child's toy top spinning very fast and tracking sporatically (walking) before settling and holding one spot on the floor before time slows the rotation and the top begins to wobble and fall.

At close ranges the bullet is over stabilized due to a too fast twist rate (rpms) that actually fights the bullet off the straight line pathkind of like trying to stay on a merry-go-round that is spinning fast, or that one ride at the fair that pushes you back against the wall and make you feel heavy. As the bullet looses velocity and rpms there is less centrifugal force pulling the bullet axis off the intended travel line. This is also why at longer ranges groups open up, the bullet isn't fast enough (both velocity and rpms, more importantly rpms) to prevent yaw or keep the bullet axis on the intended travel line.

This does not really apply to say, a .44 mag with a heavy boolit in a 1 in 20" twist.
You can see it with a 240 gr boolit in the .44 S&W watching through a scope. It goes away with a 250 gr boolit. Yet I shot 1/2" groups at 50 meters with the 240 gr. The only thing that happened at long range was a difference in POI.
I see groups double from 50 to 100 yards but then shoot a very small group at 200, not much larger then the 100 yard group.