can anyone give me some tips and equations on long range shooting? i consider anything past 300 or 400 yards long range...
wind drift, how to compensate for humitidy, elevation, whats the corriolis effect, etc. i wont be shooting far enough to have to use some of these things but i would still like to have an education about them. so any equations and tips you can provide would be appreciated.
thanks guys!
dylan
There are several but Billy,s is www.handloads.com/calc Fogure your own load.This will get you going.The Coriolis effect is explained in wikipedia.Basically it is,an object will move to the right in the northern hemisphere and to the left in the southern hemesphere,but stay stationary at the equator.As to humidity/elevation,put "humidity,elevation effect on bullet" on your search and there is a lot on both.Thats a lot of intresting reading. ,,,sam.
also how to i actually figure out my elevation and what will it do to my bullet compared to somewhere with lower or higher elevation?
another thing...what scopes are good and what arent? will the bushnell sportsman 4-12x40 AO scope that i have on my 30-06 work for long range? would a $100 barska with 40x zoom hold a zero or do i get what i pay for? and are the one piece scope bases better for long range than the two piece ones?
Shooter was just on TNT last night!Watched it agian naturaly.
same here. ive watched it too many times...i know pretty much all the lines said in it. i was switchin back and forth between that and ron white behavioral problems.
As far as my advice and hints to long range shooting, I suggest taking the largest caliber as possible, preferably .50, and the weapon with the highest rate of fire. Unleash as many rounds as possible in the shortest time possible. Go for "Accuracy by volume"!
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Rifleman, spend about 40 dollars and get Sierra Bullet's Ballistic Software. It's probably the best around as it's ballistic properties for their bullets are based on actual firing tests, not just calculations made from bullet shapes. I've used if for years and have found it to be within 1/4 MOA at all ranges up to 1000 yards for reality. See what the wind drift is for different bullets at different ranges for several wind speeds and directions. It's an education. And easy to use with great graphics and data.
Coreolis? Forget it for ranges up to about 1500 yards. I've used the same windage zero's for .308, .30-06. .264 Win. Mag. 7mm Rem. Mag. and three different 30 caliber magnums from 100 yards to 1000 yards in competition. If there was any coreolis effect, it was too small to measure. Rifle's don't use elevation angles greater than 1 degree for the ranges they're typically shot at. But I've worked on and operated computers used to calculate gun elevation for large caliber shipboard naval guns that did have a setting for latitude on the earth to compensate for this effect. Corrections were needed as the gun elevation angle for maximum range (up to 22 miles depending on caliber) was between 35 and 40 degrees. But the amout of correction was negligable for the first couple of miles of range. At greater ranges (in miles), the windage corrections started to get noticable.
Scopes for long range usually work best if they're mounted on a one-piece base with a 20 to 30 minute of angle slope on it. This is because of the 20 to 40 MOA elevation needed to zero at long range and high power scopes have only 20 MOA of adjustment from center to the upper stop on the elevation knob.
If accuracy's important, note that the more recoil a rifle has the harder it is to shoot accurate. I'd go with nothing larger than 30 caliber and 26 caliber cartridges have been about standard for competition for several years.
Thats strange because the last I knew it was the .338 and .50 cal they were making those 2000yd shots with.Did they change to .30cal and smaller? ,,,sam.
The posters are correct that this effect is negligible for rifle shooting. It really only comes into play when the projectile is crossing a significant difference in latitude.
Just for info, it (Coriolis) is just a mathematical way to describe how moving objects apparently deflect because we are on a rotating orb. If you were to sit on the projectile you would feel not acceleration either left or right but would think you are going straight, and indeed you are... relative to your viewpoint on the projectile or to an observer at a fixed point above you. But to an observer on the rotating orb it appears the projectile path veers because of a different frame of reference.
The effect exists because the earth is spinning on its axis eastward.
Case 1: Shooting north (in the northern hemisphere)
Imagine an artillery piece just above the equator, where the earth is spinning eastward at about 1000 mph, and pointed north along a longitude line. Your target is on that same longitude line and a long ways off. You might expect (and compute) the shot to land on that longitude line, and on the target, but it doesn't. Because of the eastern assist (technically a velocity vector in the direction of rotation) it lands slightly to the east. You aimed due north, shot due north, but the projectile didn't land due north, it landed just east of the longitude line. It sure as heck looks like something pushed the projectile to the right when you looked down the barrel of the cannon. You would even 'see' a curved path. What force caused this curve? None really, it's just a matter of frame of reference. The projectile did go north, it's just that it also had some eastward momentum too that we didn't account for.
Newton's laws say that if something in motion is deflected a force must be acting on it. To make Newton's laws work in this frame of reference (from the observer on the spinning object) a force has to exist, and the Coriolis force and forumlas were created to make this work out mathematically in this frame of reference.
Experiment 1). Using some gum, stick a marble on the edge of a 12" phonograph record and draw a white line from the marble to the spindle in the center. Turn on the turntable to its highest speed, spinning counterclockwise. When the marble comes by, flick it (not too hard) directly toward the spindle. It will miss to the right because in addition to the 'north' velocity you imparted to the marble, it also had some 'east' velocity. If the marble left a trail it would look like a curved line just missing the spindle to the right. If you imagine yourself a tiny person shooting the marble at the spindle it would look like the marble curved to the right.
Case 2: Shooting south
Shooting southward (say from very close to the north pole where the earth is spinning at only some few feet per hour) you will get a minimal easterly assist, but the earth will turn from under the line of shot and you wind up hitting to the right of your target again.
Experiment 2). Put a marble on top of a globe, at the north pole. Place a wastebasket under the globe where it will catch the marble when if falls off as it crosses the equator. Spin the globe eastward (counterclockwise from above the north pole). Push the marble off the north pole toward the wastebasket when Miami is directly on the line from north pole to wastebasket. The marble doesn't cross Miami, but perhaps crosses Houston or L.A. (because the globe was spinning under it) and then goes into the wastbasket. The marble took a direct and straight path to the wastebasket as you can clearly see. But imagine you were a tiny person at the pole, looking thru your aiming scope on your marble gun at Miami. You 'shot' at Miami, but your marble bullet missed to the right and hit Houston or L.A. To you it looks like something pushed the marble bullet to the right.
The effect is latitude dependent so there might be a slight difference in how much the preceived effect is if you sight your rifle at the equator and then go to the arctic, and are shooting REALLY far, but not much.
Case 3: shooting east or west on the equator
If you are on the equator and shoot in the direction of rotation, the eastward assist doesn't deflect the bullet but adds to its relative velocity and makes the bullet seem 'lighter'. This is why space missiles are lauched from as far south as possible and to the east. It adds 1000 mph to the velocity vector and there requires less fuel to get those puppies into space. Shooting westward (opposite the direction of rotation) would similarly make the bullet or rocket seem 'heavier'.
Another effect: Bullet spin
I have read that because bullets from a rifle typically spin to the right they want to move that way and that likely is more important than Coriolis for short distances, but it is not much either. Theory says this: Let's say you line up two targets on a laser line, one at 100 yds and one directly behind at some further distance. You shoot dead center on the first target but when the bullet reaches the further target it will be ever so slightly to the right of dead center because of the bullet spin to the right.
I think that when I first started looking at ballistics in the '60s the common wisdom was that this was significant but I think further experiments and measurements say that this is not the case.
The posters are correct that this effect is negligible for rifle shooting. It really only comes into play when the projectile is crossing a significant difference in latitude.
Just for info, it (Coriolis) is just a mathematical way to describe how moving objects apparently deflect because we are on a rotating orb. If you were to sit on the projectile you would feel not acceleration either left or right but would think you are going straight, and indeed you are... relative to your viewpoint on the projectile or to an observer at a fixed point above you. But to an observer on the rotating orb it appears the projectile path veers because of a different frame of reference.
The effect exists because the earth is spinning on its axis eastward.
Case 1: Shooting north (in the northern hemisphere)
Imagine an artillery piece just above the equator, where the earth is spinning eastward at about 1000 mph, and pointed north along a longitude line. Your target is on that same longitude line and a long ways off. You might expect (and compute) the shot to land on that longitude line, and on the target, but it doesn't. Because of the eastern assist (technically a velocity vector in the direction of rotation) it lands slightly to the east. You aimed due north, shot due north, but the projectile didn't land due north, it landed just east of the longitude line. It sure as heck looks like something pushed the projectile to the right when you looked down the barrel of the cannon. You would even 'see' a curved path. What force caused this curve? None really, it's just a matter of frame of reference. The projectile did go north, it's just that it also had some eastward momentum too that we didn't account for.
Newton's laws say that if something in motion is deflected a force must be acting on it. To make Newton's laws work in this frame of reference (from the observer on the spinning object) a force has to exist, and the Coriolis force and forumlas were created to make this work out mathematically in this frame of reference.
Experiment 1). Using some gum, stick a marble on the edge of a 12" phonograph record and draw a white line from the marble to the spindle in the center. Turn on the turntable to its highest speed, spinning counterclockwise. When the marble comes by, flick it (not too hard) directly toward the spindle. It will miss to the right because in addition to the 'north' velocity you imparted to the marble, it also had some 'east' velocity. If the marble left a trail it would look like a curved line just missing the spindle to the right. If you imagine yourself a tiny person shooting the marble at the spindle it would look like the marble curved to the right.
Case 2: Shooting south
Shooting southward (say from very close to the north pole where the earth is spinning at only some few feet per hour) you will get a minimal easterly assist, but the earth will turn from under the line of shot and you wind up hitting to the right of your target again.
Experiment 2). Put a marble on top of a globe, at the north pole. Place a wastebasket under the globe where it will catch the marble when if falls off as it crosses the equator. Spin the globe eastward (counterclockwise from above the north pole). Push the marble off the north pole toward the wastebasket when Miami is directly on the line from north pole to wastebasket. The marble doesn't cross Miami, but perhaps crosses Houston or L.A. (because the globe was spinning under it) and then goes into the wastbasket. The marble took a direct and straight path to the wastebasket as you can clearly see. But imagine you were a tiny person at the pole, looking thru your aiming scope on your marble gun at Miami. You 'shot' at Miami, but your marble bullet missed to the right and hit Houston or L.A. To you it looks like something pushed the marble bullet to the right.
The effect is latitude dependent so there might be a slight difference in how much the preceived effect is if you sight your rifle at the equator and then go to the arctic, and are shooting REALLY far, but not much.
Case 3: shooting east or west on the equator
If you are on the equator and shoot in the direction of rotation, the eastward assist doesn't deflect the bullet but adds to its relative velocity and makes the bullet seem 'lighter'. This is why space missiles are lauched from as far south as possible and to the east. It adds 1000 mph to the velocity vector and there requires less fuel to get those puppies into space. Shooting westward (opposite the direction of rotation) would similarly make the bullet or rocket seem 'heavier'.
Another effect: Bullet spin
I have read that because bullets from a rifle typically spin to the right they want to move that way and that likely is more important than Coriolis for short distances, but it is not much either. Theory says this: Let's say you line up two targets on a laser line, one at 100 yds and one directly behind at some further distance. You shoot dead center on the first target but when the bullet reaches the further target it will be ever so slightly to the right of dead center because of the bullet spin to the right.
I think that when I first started looking at ballistics in the '60s the common wisdom was that this was significant but I think further experiments and measurements say that this is not the case.
I'm not a math geek, I just play one on the internet.
wow thanks for the indepth description!!
my 22 can be zeroed at 50 yards but when i got for 175 or something the bullet will hit wayyyy right, about 16 clicks worth even on a calm day. the bullet spin theory explains it though!
Please dont open up on a game animal at that range until you completely understand the whys and ifs of what you are doing.That is the first lesson of long range.Range being in my books anything over about 175 yards. Not a gripe just advice!
Please dont open up on a game animal at that range until you completely understand the whys and ifs of what you are doing.That is the first lesson of long range.Range being in my books anything over about 175 yards. Not a gripe just advice!
my 22 can be zeroed at 50 yards but when i got for 175 or something the bullet will hit wayyyy right, about 16 clicks worth even on a calm day. the bullet spin theory explains it though!
I don't think it's gyroscopic precession caused by bullet spin. I've shot my Anschutz .22 match rifle at ranges of 50, 100 and 200 yards in competition. Windage zeros at all ranges are within 1/4 MOA of each other. No drift observed in zero wind conditions.
Bobvonb comments:
Quote:
I think that when I first started looking at ballistics in the '60s the common wisdom was that this was significant but I think further experiments and measurements say that this is not the case.
It was a common belief that spinning bullets precessed in the direction of spin for decades. Most interesting was the report of some folks that their bullets precessed left with a right hand twist and others said their right hand twist rifles caused bullets to precess, or drift to the right. This pretty much died out when a competitors put spirit level on their front sight, mounted the front sight base on a band clamped onto the muzzle, then with a level on the windage arm of the rear sight and it level, set the front sight's level to agree. Then the elevation slide moved in the true vertical for 45 to 50 MOA elevation.
That's what was often needed for an elevation change from boresight to a 1000 yard zero. It was the cant on the rifle's sights that caused the bullets to require more windage correction as range increased. The correction is/was always opposite to the direction of cant.
But with service rifles in competition where spirit levels are not allowed, there's still folks around who believe the bullets drift sideways from rifling twist; most to the right but a few to the left. All the barrels have right hand twists.
Gotta' be with BartB on this one.When tested,every case I ever heard of,there was no substantiation that bullet spin caused bullet drift.Bullets leave the muzzle slightly off if the sight level is allowed to tilt one way or the other. ,,,sam.
Rifleman14 say:I don't think it's gyroscopic precession caused by bullet spin. I've shot my Anschutz .22 match rifle at ranges of 50, 100 and 200 yards in competition. Windage zeros at all ranges are within 1/4 MOA of each other. No drift observed in zero wind conditions.
Bobvonb comments:It was a common belief that spinning bullets precessed in the direction of spin for decades. Most interesting was the report of some folks that their bullets precessed left with a right hand twist and others said their right hand twist rifles caused bullets to precess, or drift to the right. This pretty much died out when a competitors put spirit level on their front sight, mounted the front sight base on a band clamped onto the muzzle, then with a level on the windage arm of the rear sight and it level, set the front sight's level to agree. Then the elevation slide moved in the true vertical for 45 to 50 MOA elevation.
That's what was often needed for an elevation change from boresight to a 1000 yard zero. It was the cant on the rifle's sights that caused the bullets to require more windage correction as range increased. The correction is/was always opposite to the direction of cant.
But with service rifles in competition where spirit levels are not allowed, there's still folks around who believe the bullets drift sideways from rifling twist; most to the right but a few to the left. All the barrels have right hand twists.
judging how i didnt understand half of that, theres a lot i need to learn lol
