The Surgeon
Active Fanatic
How many long range shooters try to account for Spin Drift? At what yardage do you begging to worry about the drift of the bullet, as it relates to the twist of the barrel?
Spin Drift...
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dennishoddy
Moderator
I'm not a long range shooter by any means, but have a co-worker that is, so I tend to keep my mouth shut and listen to him.
Spin Drift will drift the path of the bullet to the right when fired from a barrel with a right hand rifling twist, as I understand it.
I believe it only makes a significant difference out past 600 yds. Maybe a little further.
He is currently shooting a .338 Lapua.
They have been hitting 5" gongs at 600 yds pretty regular. I know that's a chip shot for a real long range shooter, but they are learning.
Spin Drift will drift the path of the bullet to the right when fired from a barrel with a right hand rifling twist, as I understand it.
I believe it only makes a significant difference out past 600 yds. Maybe a little further.
He is currently shooting a .338 Lapua.
They have been hitting 5" gongs at 600 yds pretty regular. I know that's a chip shot for a real long range shooter, but they are learning.
The Surgeon
Active Fanatic
Your caliber, your velocity, your bullet weight. I am looking for an individuals perspective on the subject of Spin Drift.
Ksmirk
Well-Known Fanatic
The reasoning behind spin drift I really doubt were gonna be shooting that far for this to have any effect from what I have been told you would worry more about the curvature of the earth than to worry about spin drift. Like Troy said (don't tell him I agree with him or his head will swell) the wind is going to be more effect than anything, yes shooting angle will jack with your range dopes but that is a constant so you can overcome BUT the wind is that one thing in long range that will kick even the most seasoned LR shooters ass every now and again.
I recall one day shooting over a creek, shot was only 450 yards chip shot right? WRONG I doped the wind and touched a round off only to see a splash opposite what I called the wind! WTF! really got on the scope and touched off another same splash! ok I'm getting a touch pissy missing a 6" plate at 450 that's just stupid UNTIL I really got to looking that little 450 yard shot had 3 wind direction changes and here I only read the wind at my location DUH adjusted for wind dope and touched off another splash in the dirt! got up from the rifle went and drank a frosty and quit for the day. Sometimes that wind will just work you over and no reason to send more SMK's into the dirt than needed LOL Later,
Kirk
I recall one day shooting over a creek, shot was only 450 yards chip shot right? WRONG I doped the wind and touched a round off only to see a splash opposite what I called the wind! WTF! really got on the scope and touched off another same splash! ok I'm getting a touch pissy missing a 6" plate at 450 that's just stupid UNTIL I really got to looking that little 450 yard shot had 3 wind direction changes and here I only read the wind at my location DUH adjusted for wind dope and touched off another splash in the dirt! got up from the rifle went and drank a frosty and quit for the day. Sometimes that wind will just work you over and no reason to send more SMK's into the dirt than needed LOL Later,
Kirk
The Surgeon
Active Fanatic
Would one agree that to measure spin drift you would need a day of calm weather?
Ksmirk
Well-Known Fanatic
Dead calm day, rest that will NOT move, hydraulic trigger actuator and a lot of luck. Don't take this as actual fact but I'm wanting to say spin drift equals out to about .75" at 1K. There are so many other factors that play into LR that is one of them I just never paid attention too! that dang wind has enough of my attention.
Funny all the little things people come up with to explain that little itty bitty variance in groups, all of these tricks to bring out the most accuracy in a rifle and while some folks can actually see a difference I never could, I tried a mess of those tricks and while there are a few that do work many I could never see any difference. I know the spin drift factor is there it's just a given BUT I think today it's just something that folks throw out there to sound cool. Later,
Kirk
Funny all the little things people come up with to explain that little itty bitty variance in groups, all of these tricks to bring out the most accuracy in a rifle and while some folks can actually see a difference I never could, I tried a mess of those tricks and while there are a few that do work many I could never see any difference. I know the spin drift factor is there it's just a given BUT I think today it's just something that folks throw out there to sound cool. Later,
Kirk
The Surgeon
Active Fanatic
Shooting past a grand is fairly a mute point for me, but never the less spin drift is an interesting phenomenon.
So in a nut shell, basically no one really accounts for it?
So in a nut shell, basically no one really accounts for it?
StealthESW
Well-Known Fanatic
So, it's like this. Two guys at an outdoor range. First guy hits the target dead center. Second guy fires and hits just right of center and says, "Damn, missed. Missed because of spin drift!"
dennishoddy
Moderator
There are times, when my couriosity about the "questions" being asked, may actually be turn out to be "feelers" by the OP to judge those replying.
I also know of a very fine long range rifle builder that sells rifles marketed with the name Surgeon.
Are my instincts correct?
Ksmirk
Well-Known Fanatic
Pretty sure that Surgeon is not Preston granted it's been years since I spoke to him last but I'm pretty sure he didn't move to Geary as his shop is still or was in the same place last time I went back to Prague. Later,
Kirk
Kirk
The Surgeon
Active Fanatic
It is just a question, try not to read more in to it than there is. Gees! For the question as to me being related to Surgeon Rifles. No I am not related to Surgeon Rifles in any way, nor am I Preston. Dennis, has anyone told you that you may be a bit paranoid?
dennishoddy
Moderator
HaHa! Never. Just intuitive at times.
Wrong on this occasion, let's get back to the discussion.
As Kirk and Troy have said, wind is a much bigger factor than any of the external factors including the Magnus and Coriolis effect.
In the Mid 70's I joined the Army Reserve after 5 1/2 years active. I had the option to do my summer camp at Camp Perry National Matches as a volunteer. Chose the night shift so I could watch the 1K rifle matches. I believe the 7mm Norma mag was king at that time with open sights.
There were flags every so often showing wind direction. They don't have ok winds, but the flags were doing the same that Kirk talked about. Some moving one direction and others moving another.
Shoot one shot, measure the humidity, pressure, and load the next round on the line.
Now I understand they have small hand held calculators that do all of that for them.
dennishoddy
Moderator
I have the body in my freezer if you don't believe me!
Iggie
Well-Known Fanatic
Sorry about that dennis was testing a catapult... thought the alien would be funny...
Ben-Sons
Well-Known Fanatic
Ahh, a topic near and dear to my heart... Spin drift( not the lil green men) M-24 with 175gr boat tail hollow tip I'll correct .9 MOA @1000y (round up to 1)
Wind +/- spin drift= center mass
Wind +/- spin drift= center mass
Ben-Sons
Well-Known Fanatic
.3moa shift @500 but that is less noticeable of an error.
1.5" vs 9.1"
1.5" vs 9.1"
Kelso_G17
Fanatic
If you're going in depth, there's some good reading to be had about this in F-Class shooting publishings. Opinions vary, but there seems to be some very common points being made out to those long distances.
I had the same questions when we started shooting out to 1600 yds. It was confusing to group five shots in overlapping holes at 300, then missing the 10" plate at those super long ranges. Reading the mirage, and a few first focal plane mil-dots, and a calculating ipod app helped a lot. Gunsmith recommended the reads to me, I'll pass it along.
I had the same questions when we started shooting out to 1600 yds. It was confusing to group five shots in overlapping holes at 300, then missing the 10" plate at those super long ranges. Reading the mirage, and a few first focal plane mil-dots, and a calculating ipod app helped a lot. Gunsmith recommended the reads to me, I'll pass it along.
