Richard references one of the main issue with people sending their optics back is due to spin drift due to the bullet traveling down the rifling. While i could understand the effect, is it that drastic?
Range Report Spin drift that drastic?
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I can’t wait for Lowlight to chime in.
Yes, it is. For my rifle, it’ is 6.12 inches at 1000 yards. Spindrift is determined by stability factor and time of flight.
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Kind of what i was hoping for though maybe i should've just googled to find out myself. Some of what he claimed seemed just way off base.
Lol i forgotten about that video
Three friends and I were shooting side by side at a match on the 1000Y plate. Wind was switching that day back and forth. We all had to hold more left, .1 to .2 mil more, when there was left to right, compared to when the wind was going right to left and that's exactly what our ballistic programs called for at the time.
The way the stage worked is with 10 rounds you had to decide whether to shoot the easy targets worth less points or any combination of targets, each 100Y farther the targets were worth more points, with the 1000Y worth the most. We cycled through the whole squad, 1 shot each, so it was a long stage and a long time before it was time for each person to shoot again, which in turn gave a new wind condition for each individual shot. So when it was my turn I started and stayed at 1000Y which was a good decision because out of my squad I won that stage with 8 out of 10. Fortunately at this range there were 3 wind flags so estimating wind was fairly easy.
It was then that I started drinking the spinD kool-aid.
The way the stage worked is with 10 rounds you had to decide whether to shoot the easy targets worth less points or any combination of targets, each 100Y farther the targets were worth more points, with the 1000Y worth the most. We cycled through the whole squad, 1 shot each, so it was a long stage and a long time before it was time for each person to shoot again, which in turn gave a new wind condition for each individual shot. So when it was my turn I started and stayed at 1000Y which was a good decision because out of my squad I won that stage with 8 out of 10. Fortunately at this range there were 3 wind flags so estimating wind was fairly easy.
It was then that I started drinking the spinD kool-aid.
I don’t think anyone argues SD is real. The big rub is that many ballistic solvers over compensate for it the shorter ranges. Depending on caliber and MV, it usually isn’t a factor for many long range bullets until you approach 1000y or so, .308 maybe 600y. But many ballistic solvers, AB, for example add to much SD compensation inside those ranges. It generally won’t make you miss if you take it out. My 6.5 using AB at 650 on a typical day has me adding .2 mils for SD. I ignore that and I still get hits. If I ignore it at 1200, I almost always miss.
Know your rifle and ammo.
Know your rifle and ammo.
Agree with above. I have found after shooting for a while with the Kestrel 5700 with AB that SD was often over compensated for those ranges between around 500-1000. Have heard others echo same.
How are you guys able to determine ballistic solvers over compensate for SD?
By shooting.
I've got three ballistic solvers, Applied Ballistics, Ballistics AE and Trasol. All three come up with very similar results for SD, My scope has .1 mil clicks so, .1 mil is the finest resolution I can use. At 500 yards all three of the solvers call for .1 mil (rounded up) which is 1.8 inches (at 500 yards). Shooting a 1 MOA target at 500 yards 1.8-inch error can be the difference between a miss and a hit. Looking at how SD is calculated, I don't see how any solver can overestimate the effect of SD, the math is the math.
The science is there, no doubt.
Two schools of thought on dealing with it.
Dial it out and work the wind
Don't dial it out and work the wind.
Points to be had for either.
A couple points to ponder. Wind, science and art-sure the program tells you to hold or dial x amount for the wind-but you have to work that wind solution in the area you are in so that "formula" isn't an absolute.
The other is you reading the wind properly, kind of goes along with applying it to the terrain, etc.
Two schools of thought on dealing with it.
Dial it out and work the wind
Don't dial it out and work the wind.
Points to be had for either.
A couple points to ponder. Wind, science and art-sure the program tells you to hold or dial x amount for the wind-but you have to work that wind solution in the area you are in so that "formula" isn't an absolute.
The other is you reading the wind properly, kind of goes along with applying it to the terrain, etc.
This mirrors my experience with Kestrel 5700 AB.
These numbers are wrong, period ...
All the software referenced uses 3DOF, which does not include the variables to determine SD, instead, they use a Flat Rate value based on TOF.
4DOF can manage a certain amount of it, and if you look at the Hornady data on it, it really doesn't hit one minute with a 6.5 until 1200 to 1500 yards based on the speed of the bullet. With a 308 and slower velocities you see it around 1100 yards, but in my experience that is also incorrect, because it really doesn't show up until you get past transonic.
Supersonic flight is not a big deal unless you overspin the bullet. Even then, it's still not nearly as much as the software claims. Again, your software cannot figure it, not enough information and not enough computing power. You need a 6DOF calculation and these things are 3DOF.
Wind does have an effect, as does the rifling, the muzzle velocity, the shooter, all this adds up, which if you keep listening to this BS, it screams for a left-hand twist barrel. If we are constantly adding drifts and errors to the right, why are we not offsetting this with a left-hand twist? Everyone preaches SD as being a calculated error factor, yet no one is advocating for a fix. I personally never see it. I shoot a ton, I shoot a ton at distance, I shoot a ton in the wind from both directions and still, I refuse to use it but promise I will hit more shit than most.
That brings me back to the wind and this software.
This past weekend, a Military guy arrives after we are had already been shooting, he has a 338 and is going to 2000 yards, his Kestrel AB 5700 gave him 5.7 Mils of wind under the conditions. Guess what, we were only 1.2 at 2600 and at 2000 he needed about .8 Mils of wind. So for the guys who read this shit and believe it wholeheartedly, explain how right they are when the wind error is 5 Mils
They are overreaching by a magnitude, in my experience if they say it is 1 MOA it's really about 1/2 MOA, so any SD number you see, cut it in half. That was my experience inside 1000 yards, that is my experience shooting to 2500 yards. Cut their BS in 1/2 ...
My final fall back, how the fuck did I graduate Sniper School shooting a lame ass 173 gr to 1000 yards and not once were the words "Spin Drift" ever mentioned in a Marine Corps Manual or by any instructors. Zero, zilch, none at all. In all honestly, adding the SD numbers they use fuck up my wind calls.
PS, I have Left twist 260 barrel and it does not change my data.
All the software referenced uses 3DOF, which does not include the variables to determine SD, instead, they use a Flat Rate value based on TOF.
4DOF can manage a certain amount of it, and if you look at the Hornady data on it, it really doesn't hit one minute with a 6.5 until 1200 to 1500 yards based on the speed of the bullet. With a 308 and slower velocities you see it around 1100 yards, but in my experience that is also incorrect, because it really doesn't show up until you get past transonic.
Supersonic flight is not a big deal unless you overspin the bullet. Even then, it's still not nearly as much as the software claims. Again, your software cannot figure it, not enough information and not enough computing power. You need a 6DOF calculation and these things are 3DOF.
Wind does have an effect, as does the rifling, the muzzle velocity, the shooter, all this adds up, which if you keep listening to this BS, it screams for a left-hand twist barrel. If we are constantly adding drifts and errors to the right, why are we not offsetting this with a left-hand twist? Everyone preaches SD as being a calculated error factor, yet no one is advocating for a fix. I personally never see it. I shoot a ton, I shoot a ton at distance, I shoot a ton in the wind from both directions and still, I refuse to use it but promise I will hit more shit than most.
That brings me back to the wind and this software.
This past weekend, a Military guy arrives after we are had already been shooting, he has a 338 and is going to 2000 yards, his Kestrel AB 5700 gave him 5.7 Mils of wind under the conditions. Guess what, we were only 1.2 at 2600 and at 2000 he needed about .8 Mils of wind. So for the guys who read this shit and believe it wholeheartedly, explain how right they are when the wind error is 5 Mils
They are overreaching by a magnitude, in my experience if they say it is 1 MOA it's really about 1/2 MOA, so any SD number you see, cut it in half. That was my experience inside 1000 yards, that is my experience shooting to 2500 yards. Cut their BS in 1/2 ...
My final fall back, how the fuck did I graduate Sniper School shooting a lame ass 173 gr to 1000 yards and not once were the words "Spin Drift" ever mentioned in a Marine Corps Manual or by any instructors. Zero, zilch, none at all. In all honestly, adding the SD numbers they use fuck up my wind calls.
PS, I have Left twist 260 barrel and it does not change my data.
and a few other points, scope tend to have a "Curve" in them as you add in elevation. Not all scopes track correctly in this regard, as you approach the top of the elevation it moves right.
Nobody blames their poor trigger control, instead, they act as if it's a revelation to dial in 1 MOA and suddenly they can hit shit. Here is another example from this weekend, a writer jumped on the rifle. It was the one with the BEAST on it, so with the tall turrets, I can watch him cant the rifle. (He had no clue and said when we corrected him it looked crooked) at 2600 yards the noticeable amount of cant he put in the rifle moved the bullet 6 Mils ... nobody was that far off, so it was easy to see the effect. This was operator error and not SD.
Do the math for a 338 shooting to 2600 yards, with a 5 MPH wind coming from the right and note the correct to include your software's addition of SD. Post the answer here:
We used 7 MOA on average under these conditions or 1.2 Mils of adjustment to hit the 2600 yard target.
See if your computer matches this correction. This was not just my correction either, we used the same rifles and same ammunition, we were within 4 MOA of elevation across the rifles for the most part. In fact, at 4000 yards, we used 355 MOA, 353 MOA, and 360 MOA the last one being different ammo. So that is how close we were in elevation. Windage we were all between 6 MOA and 8 MOA of windage.
I have SD and CE turned off on all my software, if you believe this to be true, challenge me, come out to CO we can shoot my range to a mile, I have targets every 100 yards, if your software SD numbers are correct, I pay for the trip, if I am correct, you pay for the lesson.
Nobody blames their poor trigger control, instead, they act as if it's a revelation to dial in 1 MOA and suddenly they can hit shit. Here is another example from this weekend, a writer jumped on the rifle. It was the one with the BEAST on it, so with the tall turrets, I can watch him cant the rifle. (He had no clue and said when we corrected him it looked crooked) at 2600 yards the noticeable amount of cant he put in the rifle moved the bullet 6 Mils ... nobody was that far off, so it was easy to see the effect. This was operator error and not SD.
Do the math for a 338 shooting to 2600 yards, with a 5 MPH wind coming from the right and note the correct to include your software's addition of SD. Post the answer here:
We used 7 MOA on average under these conditions or 1.2 Mils of adjustment to hit the 2600 yard target.
See if your computer matches this correction. This was not just my correction either, we used the same rifles and same ammunition, we were within 4 MOA of elevation across the rifles for the most part. In fact, at 4000 yards, we used 355 MOA, 353 MOA, and 360 MOA the last one being different ammo. So that is how close we were in elevation. Windage we were all between 6 MOA and 8 MOA of windage.
I have SD and CE turned off on all my software, if you believe this to be true, challenge me, come out to CO we can shoot my range to a mile, I have targets every 100 yards, if your software SD numbers are correct, I pay for the trip, if I am correct, you pay for the lesson.
JBM Trajectory Drift Calculations
Nosler 300gr Custom Competition going 2750fps
5MPH wind coming from the Right with SD turned ON
Did you ever see Eddie Murphy Raw, 1/2 ! 1/2 your shit ... computer says 2.8, we used 1.2 go figure.
Nosler 300gr Custom Competition going 2750fps
5MPH wind coming from the Right with SD turned ON
Did you ever see Eddie Murphy Raw, 1/2 ! 1/2 your shit ... computer says 2.8, we used 1.2 go figure.
I was away with no access, the Felix Canyon Range is awesome, but no cell service and intermittent internet...
Just got home Tuesday Night,
Just got home Tuesday Night,
Looks epic. See you in Vegas.
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