Do you guys dial in for spin drift?

[Booney]

Is a head wind 180 degrees and a tale wind 0, or do i have that backwards.

 

[sp6x6]

It was actually great to see some one so skilled, spent a 1/2 day with him and it was ballistic bliss, he shot those 2 groups at under 3'' at 1000, then the whole day he was thinking of his next loads because those where different seating and thing, so he was going to re- verify the verify, plus he has a match in a couple weeks. I saw him shoot 45 shots and his largest group 5 @ 5 1/8 '' at 1003.

 

[CRNA]

Ok, after reviewing the chart a little more closely I thought a headwind would cause greater lift and the bullet would hit high. Likewise, I thought a tailwind decreased bullet lift and caused the bullet to hit low. I specifically remember having this conversation on here some time ago because I thought the whole idea was counter intuitive until someone stated that is why airline pilots like to have a headwind because they get more lift and can take off in a shorter distance. Someone set me straight.

 

[Bart B]

Col. Hatcher wrote in his notebook that the .30-06 drifted about 1/3 MOA at 1350 yards. So at 1000 yards, the spin drift's only about 1/4th MOA.

I and other long range shooters with high master classifications competing in long range matches use the same windage zero from 100 through 1000 yards. Considering the bullet's trajecory axis changes only about 1.5 degrees from up at the muzzle to down at a 1000-yard target, there's not enough gyroscopic precession working on the bullet over time to drift it very much.

So there's not enough to even measure easily by live firing exercises. How Col. Hatcher got his data is unknown to me.

 

[Bart B]

Ok, after reviewing the chart a little more closely I thought a headwind would cause greater lift and the bullet would hit high. Likewise, I thought a tailwind decreased bullet lift and caused the bullet to hit low. I specifically remember having this conversation on here some time ago because I thought the whole idea was counter intuitive until someone stated that is why airline pilots like to have a headwind because they get more lift and can take off in a shorter distance. Someone set me straight.

Headwinds slow bullets down, tail winds speed them up. This is what drag does at supersonic speeds of bullets.

Airplanes are way subsonic at take off. They need the increased lift to get them off the ground. The added drag caused by planes taking off into the wind is meaningless to what increased lift does. And some planes add more angle to the wing with flaps that angle down so takeoff at lower speeds will have added lift.

 

[justgoto]

Col. Hatcher wrote in his notebook that the .30-06 drifted about 1/3 MOA at 1350 yards. So at 1000 yards, the spin drift's only about 1/4th MOA.

I and other long range shooters with high master classifications competing in long range matches use the same windage zero from 100 through 1000 yards. Considering the bullet's trajecory axis changes only about 1.5 degrees from up at the muzzle to down at a 1000-yard target, there's not enough gyroscopic precession working on the bullet over time to drift it very much.

So there's not enough to even measure easily by live firing exercises. How Col. Hatcher got his data is unknown to me.

I don't see any consideration on bullet type, velocity, or even the direction of twist, (since coriolis can work against it depending on geographic location.) Blanket statements on a specific chambers isn't an accurate gauge. I myself discovered gyroscopic drift at 400 yards, when the 220gr RN would inexplicably hit 3 inches more to the right, than the 180gr SPs in my 30-06. If I would have realized what was going on beforehand, I would have understood the differences in the POIs at 200 and 300 yards weren't errors in doping wind.

As I've alluded to earlier; since I don't usually shoot very far; I try to make-up for it by shooting small targets... and one doesn't consistently hit a cold-bore shot at the 400 yard 1/2moa target, using the 180gr SPs traveling at 2560fps, in my 1 in 10 right-hand twist 30-06, in central Ohio; if one doesn't take into account the 1/4moa gyroscopic drift... and one will definitely not hit it with the 220gr RN at 2390fps, without accounting for the 1moa adjustment.

 

[Bart B]

I don't see any consideration on bullet type, velocity, or even the direction of twist, (since coriolis can work against it depending on geographic location.)

I've not seen any coriolis effect in either hemisphere from South Africa at 30 degrees south latitude to the Washington, DC area at about 40 degrees north latitude. Nobody else has either shooting their 30 (and smaller) calibers through 1000 yards. Shipboard naval gun fire computers I worked on had zero correction for both spin drift and coriolis up through 4000 yards; beyond that it grew a little bit for each 1000 yards of range.

Blanket statements on a specific chambers isn't an accurate gauge.

I think they're fine when the best long range marksman on earth in International Palma competition all agree there's no significant effect.

Looks like your next quote's a blanket statement.

I myself discovered gyroscopic drift at 400 yards, when the 220gr RN would inexplicably hit 3 inches more to the right, than the 180gr SPs in my 30-06. If I would have realized what was going on beforehand, I would have understood the differences in the POIs at 200 and 300 yards weren't errors in doping wind.

Are you convinced there wasn't a subtle crosswind invisible to the naked eye that caused that windage error? Did you do anything to see how much cross wind there was? And if you were shooting right-handed holding the rifle to your shoulder as it rested atop somthing on a bench, it's normal that heavier recoiling rounds shoot further to the right. The barrel moves that way while the bullet's going down the barrel.

David Tubb (many time Nat'l champ, US Palma Team member) didn't see any spin drift effect shooting 250-gr. bullets leaving at 2150 fps from his .308 Win. at 800 through 1000 yard targets in all directions. I specifically asked him about that at a match when I learned he used them. The rest of us used 190's or 200's and we didn't see any effect. But his 250's bucked the wind better than our lighter bullets leaving faster.

...and one doesn't consistently hit a cold-bore shot at the 400 yard 1/2moa target, using the 180gr SPs traveling at 2560fps, in my 1 in 10 right-hand twist 30-06, in central Ohio; if one doesn't take into account the 1/4moa gyroscopic drift... and one will definitely not hit it with the 220gr RN at 2390fps, without accounting for the 1moa adjustment.

I and many others see no difference between the first shot from a cold bore to the 10th through 20th when the bore's very, very hot.

Spin drift ain't linear from zero to many yards down range. If it's 1/4th MOA at 1000 yards, it will be about 1/10th MOA (probably less) at 400. Spin drift's almost directly proportonal to the spinning object's spin axis angle change or drop per hundred yards. There's very little change from 0 to 400, quite a lot from 0 to 1000.

======================================

I know some folks are convinced that coriolis and spin drift are very noticable in their shooting events. Having shot with, and been one of, and sometimes out shot, the top ranked long range competitors in the USA (world, too, in International Palma and Goodwill Matches), none of us ever use, think about, discuss, adust for, nor even care about.....spin drift or coriolis. 'Tain't enough to be concerned about.

 

[sp6x6]

My bench buddy that I just shot with this week adjust for it. In you last post , you just said , it my be 1/4 moa. Thats 2 1/2 at 1000. That wouldnt matter to me I cant shoot that good or have rifles that do. This guy can, and I saw it with my own 2 eyes.He seems to do all that you mention in bench, he was smoking rnds out. He told me if wind is good he put 10 down range in 18 seconds. We where at archery shooting and he missed the 2 1/2 bull and said I CAN SHOOT BETTER than that at 1000, of course I thought he was joking. We use to have a 1000 yrd. range where I LIVE. Lost it due to politics and a sub division.I heard that it was ideal for very little wind, this is where this group of guys SHOT. I am not speaking for this guy. But after seeing him shot, I honestly believe he will break his own world record,as small group light gun, as he did in 2010. Because he shot 2 5 shot groups when I went out with him, but different loads and string. But within 2 wks. he shot back to back 5 shot groups that did. He is worried right now because his mentor is tearing it up and some of his records are on the burner. His game is Penn. style bench, light and heavy. When I was at his house he had 7 or 8 world record plaques, and 2 of his shooting friends also have shot WR. So I believe what he told me, and I like your always informative posts.

 

[load]

Col. Hatcher wrote in his notebook that the .30-06 drifted about 1/3 MOA at 1350 yards. So at 1000 yards, the spin drift's only about 1/4th MOA.

I and other long range shooters with high master classifications competing in long range matches use the same windage zero from 100 through 1000 yards. Considering the bullet's trajecory axis changes only about 1.5 degrees from up at the muzzle to down at a 1000-yard target, there's not enough gyroscopic precession working on the bullet over time to drift it very much.

So there's not enough to even measure easily by live firing exercises. How Col. Hatcher got his data is unknown to me.

buzzz next answer

 

[justgoto]

I've turned on my private messaging. If your opposition to known and proven physics is a ruse to confuse the enemies of the free world, please message me and explain. If your plea is more convincing than this latest reply, I'll edit this post accordingly and let the subject drop. Either way I'm letting it drop, you can continue the argument with Britannica if you so desire.

Nobody else has [seen any coriolis effect] either shooting their 30 (and smaller) calibers through 1000 yards.

This site has plenty of people that have. And since your statement has a caveat, evidently, you do see the coriolis effect with calibers larger than 30cal.

Shipboard naval gun fire computers I worked on had zero correction for both spin drift and coriolis up through 4000 yards; beyond that it grew a little bit for each 1000 yards of range.

When the explosion form the shell is over 100 times the correction...

I think they're fine when the best long range marksman on earth in International Palma competition all agree there's no significant effect.

Fallacy: Appeal to Authority
Appeal to Authority is a logical fallacy in which a person claims to be an authority on a subject, whereas his credentials leave much to be desired. You have been using this throughout your posts in lieu of an argument. In other words, you need to use data to support your argument.

Looks like your next quote's a blanket statement.

It is as specific a statement as possible, there was nothing approaching a "blanket statement" in any of my comment.
What does blanket statement mean? - Yahoo! Answers

Are you convinced there wasn't a subtle crosswind invisible to the naked eye that caused that windage error? Did you do anything to see how much cross wind there was?

I've already tested 2 different times, ((other than when I initially tested for myself,) because internet experts couldn't do it themselves,)) they demanded I do it, wasting my time and supplies proving my point... again and again! The first test for the doubters, I shot the 180s 15minutes before the 220s. The second time I shot alternating the different weights. Same results each time!

And if you were shooting right-handed holding the rifle to your shoulder as it rested atop somthing on a bench, it's normal that heavier recoiling rounds shoot further to the right. The barrel moves that way while the bullet's going down the barrel.

Provide scientific data supporting that statement.

David Tubb (many time Nat'l champ, US Palma Team member) didn't see any spin drift effect shooting 250-gr. bullets leaving at 2150 fps from his .308 Win. at 800 through 1000 yard targets in all directions. I specifically asked him about that at a match when I learned he used them. The rest of us used 190's or 200's and we didn't see any effect. But his 250's bucked the wind better than our lighter bullets leaving faster.

My friend has won many drag race events; he is really good at it, amazing actually. He regularly provides disinformation to any of the other racers, especially when asked... no matter if they are friend or foe.

in all directions

And you are getting spindrift confused with the coriolis effect, and, (since your statement is so confused,) I'm assuming, you are compounding the error by misunderstanding the effects.

I and many others see no difference between the first shot from a cold bore to the 10th through 20th when the bore's very, very hot.

This response really has me questioning your credentials... But let's forget about the probable distraction.
I'm talking about taking one shot, as in no sighting shots. Taking one shot that day, then plan for tomorrows shot, most likely at a different distance and most certainly in completely different conditions.

Spin drift ain't linear from zero to many yards down range. If it's 1/4th MOA at 1000 yards, it will be about 1/10th MOA (probably less) at 400. Spin drift's almost directly proportonal to the spinning object's spin axis angle change or drop per hundred yards. There's very little change from 0 to 400, quite a lot from 0 to 1000.

Yes there is. Any amateur can test that theory using a ballistic calculator and find it false. Hell, the drop from the 220s were almost 3 times that of the 180s at 400 yards.
[EDIT] After reviewing my range data, the 220s were a bit more than twice the drop of the 180s at 400 yards.[/EDIT]

And there is so much wrong with that statement, I don't really care if you get it.
For those that might want to know.
Spin and Coriolis Drift

I know some folks are convinced that coriolis and spin drift are very noticable in their shooting events. Having shot with, and been one of, and sometimes out shot, the top ranked long range competitors in the USA (world, too, in International Palma and Goodwill Matches), none of us ever use, think about, discuss, adust for, nor even care about.....spin drift or coriolis. 'Tain't enough to be concerned about.

Your statements are laced with "probably" "Tain't enough" while in other statements have "didn't see any" "not seen any"; your own post contradicts itself on a regular basis.

 

[Bart B]

I've turned on my private messaging. If your opposition ......... et al.......

If you're an ignoratiolinguist, that's well said.

You might want to check your drop data for 220's vs. 180's from an '06 at 400 yards. Unless muzzle velocities are other than about normal for those bullets with max loads, the 220 drops only about 25% more than the 180 at 400 yards. There's only about 12% difference in muzzle velocity, too.

 

[Clark]

If you're an ignoratiolinguist, that's well said.

Is that like "Ignoratio Elenchi " the red herring of misdirection?

Bart, I have people following me around the internet, trying to read everything I write, and I am trying follow you around and read all your posts. It is like the south park centipede.

 

[Bart B]

Is that like "Ignoratio Elenchi " the red herring of misdirection?

No. Not like that.