looking for an expert in wind drift.

[Longshot4]

I have the opportunity to be taking varmint and whitetails at up to 500Yds. The issue is the cross wind can be up to 25 MPH and I want to keep the kick to a minimum.

I have a very accurate 222 varmint special that I could use for the varmint although I have seen there is a big problem with cross wind. In the same conditions my 308 will handle the wind well out to 275 Yds..

So now I want to have my Grandson's learn to shoot in the near future at those ranges. So I want to keep the kick down. Hopefully they will be about 10 years old when it will be time for the long range shooting.

Weight of the bullet I'm thinking no more than 100-120 for starts. The 6.0 Creedmoor sounds to me to be on the light side. The 6.5 Creedmoor seams to be heavy.

When it comes to Wind deflection is it going to be much of a issue?

Or should I be thinking in another direction?

 

[hounddawg]

I would hardly call myself a expert on wind calling. I don't think you will find many who would make that claim for themselves. However I am climbing the hill of the learning curve on mid/long range


My opinion is that for efficiency sake 100 - 110 grains is good for 6mm, 120 for 6.5 mm or split the difference with a 22-250.

I like numbers on the 6 CM and will probably build one set up for F class next winter. However I am not crazy about the 6.5 CM preferring the 6.5 Lapua or .260 Remington. Nothing against the performance of the 6.5 CM, it's balistic's are the same as the .260 Rem and 6.5 Swede. I have watched a couple of friends struggle to get good loads for the 6.5 CM and finding the right load can be challenging. These are experienced long range guys and one I know of gave up and sold his rifle. In my experience The .260 Rems are very easy to load for using 120 - 140 bullets but I never had much luck with the 107's but never really pursued them. The 120's and 140's rock.Also after running the numbers on the lighter bullets after I had learned a bit more I decided they were worthless for my purposes. For mid range minute of whitetail accuracy you might work something out. But really if you want that light of a bullet the 6CM will be more efficient.

Recoil wise that 6CM is the clear winner but the higher the bullet weight the better the wind performance. There is no free lunch with physics, a 105 gr bullet will not be able to achieve the BC that you can get a 140 gr bullet up to

 

[JeepHammer]

Most people never master the math.

Marine Corps ballistics tables will give you specific information for 7.62 NATO
The math applies once you do some long range practice and figure out what your drift is.

This might help you get a grip on the math.
http://www.millettsights.com/resources/shooting-tips/mathematics-for-precision-shooters/

Until you learn what value to assign to wind speed/direction of travel this won't work.
The only way to learn value assignment is range work, actual shooting.

 

[hounddawg]

JBM ballistics calculator will help for planning purposes. Find a bullet you like, get the BC. Go to Hogdon/Sierra/hornady or whichever load data you prefer and get some load data and plug the BC, bullet weight and a appx velocity into the calculator then compare wind drifts

One other thing though before you try and do whitetail at 600. Geta steel plate the size of the kill zone and place it at 600 and practice till you can make it go bang 9 times out of ten and think about how long it takes that bullet to get there


JBM calculator

I am going to try out a new bullet this month in hopes it will shoot in my gun. Same price as my old bullets but can save me 9 inches of wind drift at 800 in theory

 

[5whiskey]

My vote would be the good old .243 for varmint/whitetail/mild recoil/decent wind deflection (or lack therof) out to 500. You can still have 800+ ft/lbs of energy at 500 yards. That's over that of the hottest .357 or 10mm loads at the muzzle, two handgun cartridges that most don't argue are humane for harvesting deer. High BC 100 or 105 grainers should buck the wind fairly well. At least as well as any other similar caliber.

We can talk about the math of wind drift all day long, but no one can master it until the go and shoot rounds at that range, estimating wind not only where you are but in between you and the target. All that being said, it doesn't become a huge deal until after 500 yards. Even stout winds at 500 will usually deflect no more than a mil. That being said, a mil at 500 is about a shooters 18 inches or around a foot and 1/2. I've spent a fair amount of range days at that distance and beyond, and I likely wouldn't chance a shot on a whitetail in high gusty winds at 500. I don't like tracking gut shot deer. Backing back down to just 400 surprisingly changes the metric for me. Which will cover 4/5ths of your distance.

 

[Unclenick]

Longshot4,

The only thing that matters to minimizing wind drift in any chosen chambering is maximizing the ballistic coefficient of the bullet at the average velocity it will have getting to the target. This is because "wind drift" isn't really drift at all (like a leaf in the wind); it's a deflection caused by the drag vector component that is the ratio of the side wind velocity divided by the headwind due to the bullet's own velocity. This vector moves the bullet to the side much more than wind could drift it. Wm. C. Davis, Jr. gives the example of a .22 LR with 100 yards time of flight equal to the time it takes a bullet to drop 14 inches onto a table. At 100 yards, a 10 mph sidewind moves the point of impact about 5 inches. No way 10 mph wind could drift a dropping bullet that far in 14 inches of fall.

Wind deflection (excluding aerodynamic jump) is extremely easy to calculate.

Take the distance of the shot in feet (multiply yards by 3) and divide it by your muzzle velocity in ft/s. This gives you what would be the time of flight in a vacuum with no drag.

Next, take the actual time of flight from a ballistics program or a table and subtract that vacuum time of flight from it. This gives you a short time difference that is proportional to the slowing effect of drag on the bullet.

Multiply that short time difference by the sidewind velocity or, when the wind is at an angle, by the vector component of it that is sideways (the wind velocity multiplied by the cosine of the wind angle, where straight ahead is zero degrees). The result will be the bullet displacement on the target in feet (multiply by 12 to convert it to inches).

Because a higher ballistic coefficient reduces drag, making the difference between the vacuum time of flight and the actual time of flight smaller, wind deflection is minimized by using the lowest BC bullet for the weight and velocity you choose to work with. In other words, for a given velocity and bullet weight, the bullet with the least drag also has the smallest downwind drag vector component and therefore the smallest POI deflection.

 

[hounddawg]

well put Unclenick, most people want a easy fix for poor groups people look for a hundred dollar easy fix instead of admitting their technique is their main issue. Golf, shooting, fishing..we all see the guys who want to buy a place in the record books

You asked me awhile back why I quit chasing tenth's on my groups. Here is why. If you cut group size from 1 MOA to .5 MOA at 1000 yards monte carlo simulations predict you will you will improve chances of a shot hitting within a ten inch circle by a little less than 4%. At 700 yards you would see an improvement of 8 %. However then the diminishing returns factor comes to play. A improvement from .5 to .1 give you an extra 3.8 % at 700 and a extra 1.2 percent at 1000. Once you get to .5 groups time and money can be spent on other things to get more improvement.

On the other hand if you get out to the range and burn ammo and barrels up to improve your wind reading.

Improve wind/mirage skills from 5mph confidence to 3mph confidence and that 700 number goes up by 24% and if you can get that wind down to 1 mph confidence a whopping 52%.

Anyone who wants to see some real improvement in their groups go shoot out a few barrels practicing hold, trigger technique and learning wind calling

sources for numbers were from Precision Rifle Blog and Cal Zant.

http://precisionrifleblog.com/2015/04/15/how-much-does-group-size-matter/

http://precisionrifleblog.com/2015/05/14/how-much-does-wind-reading-ability-matter/

 

[5whiskey]

Improve wind/mirage skills from 5mph confidence to 3mph confidence and that 700 number goes up by 24% and if you can get that wind down to 1 mph confidence a whopping 52%.

Anyone who wants to see some real improvement in their groups go shoot out a few barrels practicing hold, trigger technique and learning wind calling

That was exactly my point. A high BC bullet helps a lot, as there is smaller adjustment needed and your margin for error will increase. At the end of the day though, learning how to call the wind and nearly exactly estimate range are the two real skills needed in long range shooting. Everything else required for a hit can be done by trained monkeys.

 

[Unclenick]

Houndawg,

I have Litz's books, but had the opposite reaction to his analysis from yours, thinking, "yay; it's not all lost in the noise". I felt like I'd seen enough almost-scratch scores in the pits over the years to realize that even a fraction of a percent hit probability improvement will gain you a point from time to time. If you can get in enough trigger time to be shooting at least occasional High Master scores, every once in awhile top mechanical precision will add another notch to your win belt. But no question, skill doping the wind is the hardest skill to develop at long ranges.

 

[hounddawg]

but had the opposite reaction to his analysis from yours, thinking, "yay; it's not all lost in the noise". I felt like I'd seen enough almost-scratch scores in the pits over the years to realize that even a fraction of a percent hit probability improvement will gain you a point from time to time

the thing is when learning is that you have to spend the money and effort where you know it will have the most effect and a lot of that is just low cost and common sense. Clean primer pockets, good trims and chamfers, consistent powder loads can be obtained with low cost but effective tools. A beam scale properly set up and used can be as precise as a 500 or 1000 dollar electronic for powder. Lee neck dies perform almost as well as Redding bushing dies. making sure primers are correctly seated and the case necks are chamfered with a correct powder charge alone can knock the SD's down and costs pretty much nothing. I anneal but seriously wonder about it's effectiveness . I would still love to see some good honest tests of it's effects on POI numbers if it has any. My gut tells me that annealing after every firing reduces flyers and I will follow my gut for the time being. That does not mean I think it has enough so to justify dropping a 1000 bucks + on a AMP. My 300 dollar Annealeeze results are acceptable.

The trick on the mechanical side of the sport being able to realize when you are at a plateau with your shooting and should be focusing elsewhere to get maximum results from time and money invested.

But no question, skill doping the wind is the hardest skill to develop at long ranges.

and the only way to learn it is to read then practice, then read again and practice again ....rinse and repeat a few thousand times

Practice can be done with a good .223 bolt gun and a mid priced scope at 200 or 300. Inexpensive ammo components and long barrel life compared to a lot of other calibers. A good .22 rimfire shot at 100 with some decent match ammo can teach a lot also.. Then see if you can shoot 1 MOA or better 20 shot groups. If that gets to easy move to 150 or 200.

Make some wind flags out of surveyors tape and those orange and white fiberglass driveway poles they sell at home depot

 

[Unclenick]

I actually like the Lee collet dies best because they don't microdraw the brass back and they keep internal donuts from forming. I do lap them and final polish with a slurry of JB Bore Compound mixed with Teflon grease and oil. That makes them run very smoothly.

Putting your time, effort, and money where you think it does you the most good is common sense for all endeavors. But we all grow in one way or another, so what needs work can change over time. Hitting a plateau is often a sign you need to shift your focus for a bit, if for no other reason than to recreate your mindset.

 

[Don Fischer]

I'm an expert in shooting in the wind. The answer is simple, don't shoot in it. Doesn't sound like the kid is even shooting yet and your thinking he need's to learn to shoot to 500yds? At 500 yds there more to consider than just wind drift!

 

[5whiskey]

At 500 yds there more to consider than just wind drift!

There is, but wind drift will be the most difficult thing to master. Bullet drop starts to come into play some after 300, but bullet drop is still fairly gradual (with the calibers were discussing) until you get past 500 yards. Is the deer at 400 or 450? Drop from 400 to 450 is 6-8 inches, still in you kill zone. From 600 to 650? Ehh, a lot more. Get it wrong and it's a miss. Plus range estimation can be simplified by a LRF if you want to pay for it. Plus you can practice manual range estimation without firing a round. You can do it driving down the road. You cannot do the same with wind drift. That being said, a 4mph wind confidence still gets you in the kill zone at 500.

 

[Road_Clam]

I shoot 600 yds weekly at my gun club. The wind varies substantially from day to day. Been shooting 600 yds for about 4 years now and I STILL have no clue as to correctly reading wind. The problem with my range layout is the wind is multi directional. The 500 flags will be 1/2 value left to right, and the 200 flags will be full value in your face. I wasted more ammo attempting to calculate holdovers and now, if shooting through a multi directional wind vortex I just wait for a wind lull and shoot. I dial in about 1/2 moa to compensate for spin drift and shoot poa at the bull. Done. Proficient wind calling is a master skill set that only the F class guys can perform consistiantly

 

[Hunter Customs]

I'm certainly no expert on wind deflection however I do a lot of shooting at an 8 inch steel plate at 500 yards. I didn't read all the post here but there looks like most have given you some real good information. As has already been stated pick you out a good ballistic calculation site, I use Hornady's. The information you need to know is bullet weight, velocity, B.C. of your bullet, the altitude where you're shooting, also temp and humidity is helpful. I got a book I've got all my info in with the exception of the temp and humidity, I don't keep those because they change so much. To make a long story short the information I'm posting is on a Remington heavy barrel rifle in 243 caliber, this rifle is easily a consistent .5 MOA rifle. Here's the info I use when shooting at and hitting the steel plate at 500 yards. The rifle is zeroed at 200 yards, bullet BC is .379, bullet weight is 95 grains Nosler Ballistic Tip, muzzle velocity is 3100 fps, drop at 500 yards is 39.2 inches, dial up correction on elevation is 2.2 mils, with a 10 mph full value wind bullet deflection is 22.5 inches the windage correction for that would be 1.2 mils. I posted this info because you said something about shooting in a full value 25 mph wind, doing the math you can see it wouldn't be hard to have a 4 foot plus wind deflection. Good luck and good shooting.

 

[hounddawg]

You have to factor terrain features in also, they can cause turbulence and turn a uprange or downrange wind into a quartering or crosswind . It is something that has to be worked at and thought about but it is not an impossible task to improve your skills. I use mirage for 5 -10 mph, it is more reliable than flags or leaves. Plenty of good info on the net on tactics.

And if you get discouraged go watch some videos of the prairie dog hunters shooting low BC bullets in windy conditions. Or the Utah milk jug challenges

 

[std7mag]

When you find an "expert in wind drift" please let us know!!
I would gladly take lessons from said person.

 

[taylorce1]

The only way to get good in the wind is to shoot in it. Either Creedmoor cartridge has a lot going for it, but if all you're hunting is white tails and varmints I'd probably get the 6mm version or a plain old .243 Win.

 

[hooligan1]

Beat the wind problem by becoming better hunters and close the distance......
Doesn't matter what you hunt with in wind, no magical round that cuts through unscathed........scoot up to those animals and killem using the wind as your brother.....

 

[tobnpr]

The real impact of wind isn't as much it's speed or relative value- but its consistency to the target
500 yards is about the distance most long-range capable centerfires start to exponentially slow (with wind reads becoming much more difficult further out), so at that range and inside isn't as tough as it could be.

Big question is whether your winds are relatively steady- or gusty?
Steady wind, consistent to the target is no more than dial and shoot. Any ballistic program (such as Strelok) on your smartphone will provide the necessary info, and a wind meter will provide the input needed for it.

Gusty winds, swirling, differing all the way to the target- that's a different animal altogether.
I'd go with a high BC, VLD hunting bullet in 6mm or 6.5. The faster you get the bullet there (velocity), the less time for external influences (wind/gravity) to affect it. I agree the .243 is a good choice for your application, though barrel life is going to be substantially less than a .308. The .308, 7-08, or .260/6.5 creed will all work fine, but with progressively less barrel life.

Honestly, to learn- I'd start with a .308. Ammo is plentiful, reasonably priced (until you get into handloading) and capable. The key, is practice ...and more practice...you won't burn up a barrel on a .308, and once you develop some skills using a "optimal" setup for your conditions will make it a cakewalk.

Learn the area you'll be shooting at, set up wind flags every 50 yards to the target and study them. You'll be surprised...