What is ELR Anyway?

[Bart B.]

I have heard similar statements from others. I always womder how they are measuring it, as a linear measurement or an angular one

Wind at 90 degrees to line of sight (top down in this chart) is my setup:


Showing wind speeds above LOS, trajectory high point about 60% of target range:

 

[Milo 2.0]

Wind at 90 degrees to line of sight (top down in this chart) is my setup:
View attachment 1051846

Showing wind speeds above LOS, trajectory high point about 60% of target range:
View attachment 1051848

Make your graph show your 1/2moa correction to 333 with the wind stopping cold turkey. Then build the other line showing no wind to 666 then entering and the correction needed. The green line has quite a sharper bend to it IMO, therefore more susceptible to disruption. You're correct in the aspect if you can't get your bullet on track at 333, there is no return, but it's far from linear. Any ballistic app utilizing a full value wind will show the farther you go the more correction that is needed, proving the correction needed is not even remotely linear. Your bullet is fighting the wind the whole way, at no point in this equation is the first third of the distance the driving factor.

 

[johnfred1965]

I would have thought more people on this site would have had a peak inside a dictionary before. One word or phrase can have many meanings. One of Litz's definitions is at transition, but he also defined it as starting at 1500 yards. I can easily accept either of those definitions. And there can be others, depending on what you are shooting. What would you consider ELR for a 22LR? 300, 400 yards? 22's, if they don't start subsonic, usually get there pretty quick. For high powered rifles, I interpret Bryan's definition of trans or subsonic to mean you are at ELR for whatever cartridge you are shooting. However, if you are shooting Artie, ELR has another meaning. THe 1500 yard definition simply gives a standard that any shooter and cartridge can be measured to. While it is a challenge for a 308win, it is a good starting point for a 338L. You can"bring what ya got" and see what you can do way out there, or as some have said you can "buy in" to an expensive rifle cartridge combo that will give you an edge, if you know how to shoot it.

I posted before I read the PRB definition. So how was my guess?

 

[johnfred1965]

I thought of another arbitrary definition "The point at which the rifle/cartridge combo needs one degree(60MOA) of come-up from a 100 yard zero" See, anyone can set a standard, Just depends on who you get to follow it. Kind of levels the playing field between the 308 and the 338, or even the 22lr!!

 

[Bart B.]

Make your graph show your 1/2moa correction to 333 with the wind stopping cold turkey. Then build the other line showing no wind to 666 then entering and the correction needed.

That is exactly what I did, 10 mph thru 333 yards first, then after 667.

No MOA correction used or plotted. Drift is charted in inches. Where do you see it drift in 1/2 MOA? The bullet drifted 9 inches or near 3 MOA in the first 333 yard band from a 10 mph crosswind

Note the bullet is at a much lower speed at 667 yards. With no wind past 333 yards, trajectory is straight after that moving the same rate sideways from the LOS all the way straight to 1000.

 

[Milo 2.0]

That is exactly what I did, 10 mph thru 333 yards first, then after 667.

No MOA correction used or plotted. Drift is charted in inches. Where do you see it drift in 1/2 MOA? The bullet drifted 9 inches or near 3 MOA in the first 333 yard band from a 10 mph crosswind

Note the bullet is at a much lower speed at 667 yards. With no wind past 333 yards, trajectory is straight after that moving the same rate sideways from the LOS all the way straight to 1000.

Do you even shoot bro?

 

[Bart B.]

Do you even shoot bro?

Do you even answer questions bro?

 

[Depart123]

Wind at 90 degrees to line of sight (top down in this chart) is my setup:
View attachment 1051846

Showing wind speeds above LOS, trajectory high point about 60% of target range:
View attachment 1051848

Thanks for the graph. The graph answers one question and raises another. What happens to the drift if the bullet moves into a wind shadow after the first 333 yds. Does it continue to drift at all, or does the drift stop?

 

[6ShotsOr5?]

A crosswind creates a lateral component to velocity. The longer the bullet is acted upon by the same wind, the greater the lateral velocity will be. The lateral velocity component will not go away suddenly in a wind shadow, but will gradually decay so little that’s it’s not even important. The lateral velocity will stop increasing in a wind shadow.

 

[Ledd Slinger]

Making it through the transonic window is where an overly tight twist can help you out. It has a lot to do with the bullet design of course, but faster RPM on a bullet is beneficial to maintaining good stability as it transitions from supersonic to subsonic speed. Or any speed for that matter.

The new 30 cal 230gr Sierra calls for a 1 in 8" twist. At the elevation I shoot and speed I will be pushing the bullet from the muzzle, a stability calculator tells me a 1 in 9" twist barrel would still give me good stability. I went with the recommended 1 in 8" anyhow. When I'm stretching these bullets out to 2K or further, any extra rotational speed on the bullet will help to maintain consistent stability as the bullet slows down. It also allows for a selection of accuracy nodes at lower speeds that may not be useable with a slower twist barrel. Just my thought process.

 

[Ledd Slinger]

I could take you to 4 ranges outside the city I live in and put this theory to rest. To 6-700 yards what you say may hold true, but stretch that in 100 yard increments 5-600 more yards and the first third of your solution has little bearing of the outcome. Wind patterns can be introduced anywhere in the flight path, making a blanket statement isn't correct. Cross a couple of drainages, throw in a wind funneling in from a draw picking up speed as it comes, spells disaster if you're counting on the first third of the distance as your wind call.

Very true. I have to deal with those exact wind call situations every fall hunting in the mountains of Montana. Can't just go off of what's in front of you. Have to look at trees and vegetation all the way to the animal and do your best to judge it. Which is also exactly why i dont own a wind meter. Doesnt do much good if its fairly calm on the bench of a ridge where im set up but i can see trees flailing around in the valley bottom or across a canyon. Its a little easier Making wind calls on the plains, but it can still get pretty tricky over there with all the gusting.

 

[Milo 2.0]

Very true. I have to deal with those exact wind call situations every fall hunting in the mountains of Montana. Can't just go off of what's in front of you. Have to look at trees and vegetation all the way to the animal and do your best to judge it. Which is also exactly why i dont own a wind meter. Doesnt do much good if its fairly calm on the bench of a ridge where im set up but i can see trees flailing around in the valley bottom or across a canyon. Its a little easier Making wind calls on the plains, but it can still get pretty tricky over there with all the gusting.

Ever since I got into LR shooting I've read how the first third of my bullets journey is impacted the most. In 9 yrs I've never been able to comprehend that aspect. Maybe subconsciously I figure it in, but if I need to cold bore 1K, I scan 500-700 and see what it will take after that. If I shoot 1450, which I do almost every outing, I'm calculating at 1K and scanning beyond.
I don't shoot ranges in clear cuts, every place I do has structure changes or barriers of some sort that affect the flight path more than the first third of he bullets time in the air. The rodeo starts at 700 most places, one range, a stretch between 5-700 dictates any shot beyond 700.
Wind is like water, it takes the path of least resistance, but when water hits a barrier, it will pool up and spread out, wind can't do that, it picks up speed to get through or around to regain it's place in the chain. I takes one big area to allow wind to make even a 40 degree turn, it'll pick up speed and climb first.

 

[Milo 2.0]

Do you even answer questions bro?

Apparently not yours?

 

[Bart B.]

Thanks for the graph. The graph answers one question and raises another. What happens to the drift if the bullet moves into a wind shadow after the first 333 yds. Does it continue to drift at all, or does the drift stop?

It continues to drift at the same rate when the wind stops. If the wind pushed the bullet to drift 1 inch for each 10 yards downrange from 323 to 333 yards, then stops blowing 333 yards downrange, the bullet continues to move in a straight line in that direction at a fixed angle to the LOS at that same rate. There's no wind to change its direction.

Sierra Bullets' software let's you set wind speed and direction in different size range bands to see what happens in such conditions. I wish it would do the same vertically and include a terrain condition.

A few have claimed the bullet turns back parallel to the LOS after the wind stops.

 

[Depart123]

It continues to drift at the same rate when the wind stops. If the wind pushed the bullet to drift 1 inch for each 10 yards downrange from 323 to 333 yards, then stops blowing 333 yards downrange, the bullet continues to move in a straight line in that direction at a fixed angle to the LOS at that same rate. There's no wind to change its direction.

Sierra Bullets' software let's you set wind speed and direction in different size range bands to see what happens in such conditions. I wish it would do the same vertically and include a terrain condition.

A few have claimed the bullet turns back parallel to the LOS after the wind stops.

I ask, because I always thought drift was the result of the wind pushing on the bullet, imparting momentum that would allow it to continue to drift in the absence of wind, just like you stated.

But a couple of engineer type folks told me that the bullet isn't pushed by wind, but the side wind causes the nose to weather vane into the wind just slightly causing the direction of drag to be offset from the mean trajectory opposite the relative wind. So the bullet is essentially dragged from it's mean trajectory.

If this is true, then as soon as the wind stops, then the relative wind travelling over the bullet from forward flight would straighten it again, putting the drag force once again in line with the mean trajectory, and there would be no more drift.

Do you have any sources to point me to that can confirm one way or the other? I'm asking because as a field shooter, it drastically affects the way I do wind math.

 

[Milo 2.0]

I ask, because I always thought drift was the result of the wind pushing on the bullet, imparting momentum that would allow it to continue to drift in the absence of wind, just like you stated.

But a couple of engineer type folks told me that the bullet isn't pushed by wind, but the side wind causes the nose to weather vane into the wind just slightly causing the direction of drag to be offset from the mean trajectory opposite the relative wind. So the bullet is essentially dragged from it's mean trajectory.

If this is true, then as soon as the wind stops, then the relative wind travelling over the bullet from forward flight would straighten it again, putting the drag force once again in line with the mean trajectory, and there would be no more drift.

Do you have any sources to point me to that can confirm one way or the other? I'm asking because as a field shooter, it drastically affects the way I do wind math.

The best thing you could do is grab a friend, or 2, go shoot on high moisture days, even in the rain, get behind a shooter with a spotting scope and watch bullet trace. I've learned as much from being a spotter as a trigger puller.
In a left to right wind one day, shooting a 5" plate at a grand, I watched my bullet cross the plane of the target I'm guessing at 900 yards and get blown back onto the target from a right wind gust. Stuff happens fast, but it was like it was frozen in time, it was my last bullet of the day and I said to myself,"you've got to be kidding", it felt good, lol

 

[Bart B.]

I ask, because I always thought drift was the result of the wind pushing on the bullet, imparting momentum that would allow it to continue to drift in the absence of wind, just like you stated.

But a couple of engineer type folks told me that the bullet isn't pushed by wind, but the side wind causes the nose to weather vane into the wind just slightly causing the direction of drag to be offset from the mean trajectory opposite the relative wind. So the bullet is essentially dragged from it's mean trajectory.

If this is true, then as soon as the wind stops, then the relative wind travelling over the bullet from forward flight would straighten it again, putting the drag force once again in line with the mean trajectory, and there would be no more drift.

Do you have any sources to point me to that can confirm one way or the other? I'm asking because as a field shooter, it drastically affects the way I do wind math.

If that's the facts then those engineers convincing you otherwise should convince Sierra Bullets to fix their software ballistic engineers helped design. Think of the glorious accolades they would get proving Sierra's software was wrong.

I'm just the messenger delivering Sierra's information. It compares favorably with my observations shooting long range matches when visible wind indicators were in only one short range band. And that of other top ranked competitive shooters.

 

[Bart B.]

In a left to right wind one day, shooting a 5" plate at a grand, I watched my bullet cross the plane of the target I'm guessing at 900 yards and get blown back onto the target from a right wind gust.

I too, have seen S shaped bullet traces through 1000 yards.

When I designed then surveyed and staked out the 1000 yard range near Byers, CO, I noted the gentle winds reversed and switched across all 6 firing line's flagged stakes. When the range flags were put up about 15 feet above grade, they too seldom all streamed the same direction and amount. At its first 1000 yard match, flags were blowing all directions. I decided to shoot my first sighter using windage zero established the day before in practise. It was off the X ring about an inch at 2 o'clock; yes, a lucky shot.

 

[Bart B.]

A crosswind creates a lateral component to velocity. The longer the bullet is acted upon by the same wind, the greater the lateral velocity will be. The lateral velocity component will not go away suddenly in a wind shadow, but will gradually decay so little that’s it’s not even important. The lateral velocity will stop increasing in a wind shadow.

3 cheers for you explaining all the right stuff. Much better than I could have. "Wind shadow" is a great term to use.

 

[Milo 2.0]

I ask, because I always thought drift was the result of the wind pushing on the bullet, imparting momentum that would allow it to continue to drift in the absence of wind, just like you stated.

But a couple of engineer type folks told me that the bullet isn't pushed by wind, but the side wind causes the nose to weather vane into the wind just slightly causing the direction of drag to be offset from the mean trajectory opposite the relative wind. So the bullet is essentially dragged from it's mean trajectory.

If this is true, then as soon as the wind stops, then the relative wind travelling over the bullet from forward flight would straighten it again, putting the drag force once again in line with the mean trajectory, and there would be no more drift.

Do you have any sources to point me to that can confirm one way or the other? I'm asking because as a field shooter, it drastically affects the way I do wind math.

One other thing you could do is shoot as many ranges as possible, in all directions. Shooting due north day after day does little in the knowledge part of this. We think we shoot the same winds often when in reality we shoot the same type of wind patterns, no 2 days are alike.
Ledd slinger said he does not use a wind meter, I will if the wind is over 15mph. One of the best tools on the market is a Kestrel 5700 with applied ballistics and link. Just say at your firing position, the wind is blowing 10mph from 8 o'clock, but you can see at 500 the wind is straightening out and slowing down. At this point I'd shoot a 7mph wind from 7 o'clock solution past 600 yards.
And the minute anyone tells you they have a grip on wind is the day they will embarrass themselves.