Wind effects at 100yds?

I was at the range yesterday testing some new ammo was getting sub par results. Im reluctant to blame to ammo as the brands being tested were Southwest and Federal GMM which both have an excellent reputation. I was shooting in to a 5-15mph headwind, but at 100yds I was thinking wind was a non factor. How much does wind effect groups sizes at 100yds? I was shooting Southwest 175 Standard and Run-N-Gun and GMM 168.
 
Re: Wind effects at 100yds?

I shoot pretty often. I shoot around 3/4MOA all day and occasionally sub 1/2MOA. My groups yesterday were 1+MOA. I was getting that with the GMM but I cant believe the Southwest was that much different. Im going to shoot some more this week before I come to a conclusion. Hopefully without wind.
 
Re: Wind effects at 100yds?

5-15 is a light breeze here. Count it as a zero effect. 100 yds those rounds are flying fast enough that it's not easily measurable.

A head wind won't stop your rounds from grouping. So it's either you or the load.

Also just because a load doesn't group at 100 doesn't mean it won't out at 200 or further. Shoot the ammo out further at least 200 preferably 300.
 
Re: Wind effects at 100yds?

A headwind should have no effect on group size at 100, unless maybe it was very gusty and knocking you off position. I have shot in a crosswind at 100 which blew my rounds 1"-1 1/2" to the right. Group size was fine though. Even the best ammo is not great in every rifle. Keep trying loads til you find one it likes, maybe try different weight bullets.
 
Re: Wind effects at 100yds?

I experienced this a while back and it was very frustrating... While I was just sitting there staring down range in frustration, I realized the target was moving slightly with the wind because the post it was on had worked loose in the ground...could this have been your issue as well?

Food for thought.
 
Re: Wind effects at 100yds?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: CrazyDonkey</div><div class="ubbcode-body">Was it the Southwest Match ammo or Run 'N Gun? Also, are you shooting the same bullet weight with the SW as you were with FGMM?</div></div>

The GMM was 168 Grain
The Southwest was 175 Grain Run-N-Gun, and Standard
I regularly handload for this rifle with 175 SMK's so the rifles twist handles the weight fine.
 
Re: Wind effects at 100yds?

I could be wrong and if I am I hope someone will correct me, but I do not think the Run 'N Gun is meant to be compared to Gold Match or SW Ammo's Match loads.

This could be why you are seeing your groups differ.
 
Re: Wind effects at 100yds?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: CrazyDonkey</div><div class="ubbcode-body">I could be wrong and if I am I hope someone will correct me, but I do not think the Run 'N Gun is meant to be compared to Gold Match or SW Ammo's Match loads.

This could be why you are seeing your groups differ.</div></div>

If you don't compare you are simply assuming. Im simply comparing for my benefit and GMM is the "Control". I was getting frustrating results accross the board that day and, after checking my rifle, this was the only other variable.
 
Re: Wind effects at 100yds?

Sorry, I misunderstood, I thought that your FGMM shot well and the SW Run 'N Gun didn't.

Do you have a thead protector on your muzzle? When that gets even a little loose it can throw shots.
 
Re: Wind effects at 100yds?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: CrazyDonkey</div><div class="ubbcode-body">Sorry, I misunderstood, I thought that your FGMM shot well and the SW Run 'N Gun didn't.

Do you have a thead protector on your muzzle? When that gets even a little loose it can throw shots. </div></div>

My barrel is not threaded.
The GMM grouped "better" but was not up to my expectations, and was not well enough for me to give up on the Southwest. More trigger time will tell the tale.
 
Re: Wind effects at 100yds?

How clean/dirty was your rifle? And is it a factory barrel or custom? I've found that when my rifle had a fact. barrel accuracy tend to diminish at around 150 rnds or so and with the custom I go about 200 or so before accuracy goes down. * THe best groups are somewher in the middle.

Or just maybe you just had a bad day at the range which happens to all of us.
 
Re: Wind effects at 100yds?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cuffm4615</div><div class="ubbcode-body">How clean/dirty was your rifle? And is it a factory barrel or custom? I've found that when my rifle had a fact. barrel accuracy tend to diminish at around 150 rnds or so and with the custom I go about 200 or so before accuracy goes down. * THe best groups are somewher in the middle.

Or just maybe you just had a bad day at the range which happens to all of us.</div></div>

It is a factory Rem 700. I keep the rifle fouled and simply run a bore snake through at the end of a range session. I recently gave to rifle a thorough cleaning prior to my last range session before this one. It probably has 50 rounds downrange since the cleaning.
 
Re: Wind effects at 100yds?

Which way were they stringing? Were they off vertically, horizontally or just all over the place? Was it cold? Did you have a heavy coat on...thus loading your bipod differently with each shot...maybe canting just a little different each shot? Do you have your action screws tightened down good? Scope rings tightened down good?

If all else fails...blame it on the Squirrels.
 
Re: Wind effects at 100yds?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: B2Riesel</div><div class="ubbcode-body">Which way were they stringing? Were they off vertically, horizontally or just all over the place? Was it cold? Did you have a heavy coat on...thus loading your bipod differently with each shot...maybe canting just a little different each shot? Do you have your action screws tightened down good? Scope rings tightened down good?

If all else fails...blame it on the Squirrels.</div></div>

The GMM was stringing vertically, as was the Standard. The Run-N-Gun would start to group then flyers. Normal Louisiana weather 70 degrees, but windy. Everything tightened to spec on the rifle. Damn those squirrels.
 
Re: Wind effects at 100yds?

For me personally...I've always found that my verticals were caused by me not loading my bipod the same every time...and then the tiny verticals were caused by me putting a pulse on the stock...I keep my thumb off as best I can and the free hand squeezing the rear bag and no where near the stock. If you are like me...I get pissy when all 5 shots in the group are not touching....because I know what the rifle can do...and I know my handloads are great...any screw ups is ME.
 
Re: Wind effects at 100yds?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: B2Riesel</div><div class="ubbcode-body">For me personally...I've always found that my verticals were caused by me not loading my bipod the same every time...and then the tiny verticals were caused by me putting a pulse on the stock...I keep my thumb off as best I can and the free hand squeezing the rear bag and no where near the stock. If you are like me...I get pissy when all 5 shots in the group are not touching....because I know what the rifle can do...and I know my handloads are great...any screw ups is ME.</div></div>

And it could be "Me"...But who wants to blame "Me". That's why I want more trigger time before I give up on the Run-N-Gun.
 
Re: Wind effects at 100yds?

With all that said...my gun is a 1/2 MOA gun...with my hand loads...I've yet to find any over priced store bought stuff that shoots less than 3/4 MOA...and most of it shoots aroun 1MOA or higher. It just doesn't like the retail stuff. I have a 26" barrel and it could boil down to finding a round that has a harmonic resonance in balance with your particular barrel...but that is getting way too geeky...so I better go back to bed.
 
Re: Wind effects at 100yds?

My gun shot 3/4 minute or so with the Southwest Match at 100, but tightened up to .6 moa average at 230 yards. I say shoot it further out.
 
Re: Wind effects at 100yds?

I was suffering the same frustration. When new my 5-R Milspec was better than expected with sub 1/2 MOA accuracy from the box.

Lately it started to string horizontal for no apparent reason. No wind, or 10 Mph, no matter at 100 yards, the groups just started to get bigger.

This last weekend I re-bedded the stock/action. Seems like the aluminum action block was stressing the action but now with a nice layer of Devcon and some risers to bring the "pillars" up to the action, in place it's back to better than it was when new.

Cold Bore shot was 1.5" high, 2nd shot .740 high, and shots 3-5 were touching, also dead on POA. That was with my "fouling ammo" which was just run off with my Dillon 650 (Kind of like Factory Ammo).

I then changed to some handloads that had proven accurate at earlier shoots. Regular "Bug Hole" groups were frequent for the rest of my range session with the best being .191" All 5 shots in what essentially looked like two shots touching each other.

I expect better performance from here out with the action being more solid and less stessed in the stock. Will "go longer" when I get my new scope.
 
Re: Wind effects at 100yds?

I'm not familiar with Southwest but if FGMM woun't shoot you have one of the few guns around it is not good in. I try to handload with the same precision the bench rest guys do and I have a hard time making better loads than FGMM. I always shoot a group or two of FGMM against a new load as a control to see if I am wasting my time or not. Why don't you do the same thing in reverse. Take some of your best loads and shoot them against the FGMM. Same conditions
 
Re: Wind effects at 100yds?

Just out of curiosity, were you shooting prone, or off a bench? I've had occasions with headwinds similar to what you described that affected my precision by blowing enough to make <span style="font-style: italic">me</span> unsteady when sitting at a bench. Definitely wasn't an effect on the projectiles, but the shooter. Probably wasn't an issue of you were shooting prone.
 
Re: Wind effects at 100yds?

I find shooting tiny 100m groups hard going. Much happier at 200m (often as tight as my 100m). When I used to shoot small bore a cup of coffee before cost me a point; a coffee and a fag (cigarette) cost me two points. All I'm saying it doesn't take much. Shooting under 2/3 of MOA takes a lot of application and under that even more so. If you read every post it you would think it was normal and easy. Its not.

Sun in the sky courses me more problems: scope in shadow/out of shadow; across or into your eyes.

Wind at 100m?? Ground wind differs from higher up and the lay of the land does odd things. So long as its basically constant and constant air pressure then it shouldn't show; other variables might.

In truth bipod loading, what its sitting on and your own position behind the rifle including head position and if you are loading your nut on the stock differently between shots might be the problem. Clothing changes can have an effect too.

I wouldn't panic until its happening over several range days.

A curry the night before can do it too.
 
Re: Wind effects at 100yds?

Yes, the wind at 10-15 can and will cause shot dispersion. It doesn't matter if it is a headwind or a full 90 degree wind. The difference between cloudy and clear skies can also cause verticle in your groupings.

If you doubt the wind, use 3-4 wind flags and look to see what the wind is doing between yourself and your target. A 168 grain bullet at 27-2800fps is affected by the wind, irregardless of its ballistic coefficient and its speed.

If you want a great education on shooting in the wind, go to Benchrest.com and ask the same question over there. When you own and shoot rifles that are capable of shooting 5-5 shot groups at .100 or smaller you would be amazed at how much the wind plays with your shots.
 
Re: Wind effects at 100yds?

I can understand stand how the different light on a 3 dimensional iron sight causes changes in impact but how does the different conditions change the angle of light on a reticle ?

Especially if you have removed the parallax from the system ?
 
Re: Wind effects at 100yds?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Mike Casselton</div><div class="ubbcode-body">Yes, the wind at 10-15 can and will cause shot dispersion. It doesn't matter if it is a headwind or a full 90 degree wind. The difference between cloudy and clear skies can also cause verticle in your groupings.

If you doubt the wind, use 3-4 wind flags and look to see what the wind is doing between yourself and your target. A 168 grain bullet at 27-2800fps is affected by the wind, irregardless of its ballistic coefficient and its speed.

If you want a great education on shooting in the wind, go to Benchrest.com and ask the same question over there. When you own and shoot rifles that are capable of shooting 5-5 shot groups at .100 or smaller you would be amazed at how much the wind plays with your shots. </div></div>

Yes, a head-wind can cause dispersion, but head-wind is not causing the OP's problem. He experienced vertical dispersion on the order of 1 to 1.5" at 100 yards. The dispersion caused purely by a variable head-wind on the order of 15 mph is tiny by comparison (less than 0.1", I believe). Want to figure it out for yourself? -- try running some numbers in a ballistic trajectory calculator.
 
Re: Wind effects at 100yds?

Other than making your eyes water, changes in light and where the sun is can have an effect. Light levels too bright and you end up drifting up into the target. White cards with a black bull are really bad. I find I get my best days shooting on dull windless days. Also you see mirage differently depending on where in the sky the sun is. All sorts of stuff is going on that can make a difference which is why experience comes in. Some wind coaches can't shoot for toffee but they can "guide" a good shot right in where others struggle. Knowing your home range and shooting it regularly helps too.

There is one thing shooting a group and another to get it into the centre of the target. Just see how many groups posted aren't anywhere near the aiming mark!

Once my rifle is zeroed I wont change it first time it seems off by a it. Too often the next time out its straight back in. Don't chase the error, but that doesn't mean you can't click to the conditions of the day. Its the reason to have a score book to watch for small changes.

No ballistic calculator can calculate the effects of a hot curry eaten the night before. Changing the beer you drink has the same effect.
 
Re: Wind effects at 100yds?

What you are doing is overlaying the effect of light as seen on Iron Sights and acting like it is effecting a scoped rifle... I have thousands of rounds in every kind of light condition and I have never see an impact change because of it.

On a 3D object light will change the angle of attack, on a 2D object like a reticle in a scope which is not being adversing effected by light as it is covered. Parallax would be a better explanation for shifts, before light would.

Mirage, been there done that got the t shirt, shooting in over 100 degrees in South Texas teaches you a thing or two about mirage and light... light is a non-issue with a scope. Irons, different animal, yes.
 
Re: Wind effects at 100yds?

No, I never said anything about iron sights and scopes.. only you, so please don't guess where I am coming from. I would agree, especially pistols, iron sights and where the sun is can have a marked effect. Even with scopes light can play tricks with your sight picture.
We are also talking beyond 100m now and I'm sure there is plenty of info from the long range boys. Mirage is a huge topic.

I have hundreds of thousands of rounds under my belt and all I'm saying we don't shoot lasers and often we only get on target by "feeling" our way there. Not quite "let the force be with you" but sometimes it feels like that. I used to shoot at some little fort near Little Rock; that was quite hot and quite competitive.
 
Re: Wind effects at 100yds?

You got me, I will ask a Long Range Boys what happens because I have no clue... Mirage is not light and that is what drives the image up, sun directly into the scope would be a problem, but again, night and day difference between saying a bright day versus cloudy day... but i have never shot long range so I will differ to those who know.
 
Re: Wind effects at 100yds?

The big thing with light is that with bright targets you tend to "push" into them. Not sure why. A nice dull target and you tend to be more consistent.

Mirrage is air turbulence from heat rising off the ground. Moisture in the air really shows it up well but where its baking hot the pure air turbulence shivers. See it at different ranges and at each stage it can seem to be going in opposite directions. At long range it definitely shifts what you see to where the target is. Who said light moves in straight lines. Research it all, you will like it; its a big subject and no one has it sussed. A bit like wind over mountains. If only shooting was so easy.

I've never got on with ballistic calculators, something you could teach me a thing about. I'm old school and believe in my shooting notes from doing the practical. Both have their merits.
 
Re: Wind effects at 100yds?

Lowlight, Yes, you do. I do have a habit of writing as if coaching to a recruit rather than taking into account to whom the question is coming from. I like the way you scrutinize every aspect; I'm a lot more laid-back to the point my shooting sucks unless I'm under pressure such as in a competition or game shooting. However, I've normally done my homework and have shot the rifle extensively so know what it will do. I don't swop my rifles often. When I was a Cold War Deterrent I did put some rounds down the range though.

When I shot in the States (mostly Camp Robinson??) I was always nicely surprised what good light there was and how over a day the weather conditions tended to be constant throughout the day. There were wind shifts but nothing too bad. I'm sure its not like that all the time but when I was over it seemed like that and for weeks at a time.
In good old Blighty you are lucky to get half an hour without something changing, cloud, wind, rain. Always something; just never take anything for granted and go with the flow.
 
Re: Wind effects at 100yds?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">What you are doing is overlaying the effect of light as seen on Iron Sights and acting like it is effecting a scoped rifle... I have thousands of rounds in every kind of light condition and I have never see an impact change because of it.

On a 3D object light will change the angle of attack, on a 2D object like a reticle in a scope which is not being adversing effected by light as it is covered. Parallax would be a better explanation for shifts, before light would.

Mirage, been there done that got the t shirt, shooting in over 100 degrees in South Texas teaches you a thing or two about mirage and light... light is a non-issue with a scope. Irons, different animal, yes. </div></div>
Frank, this is something I have been trying to wrap my head around.

The range officer at my local spot has made mention several times of horizontal shift from the morning to the afternoon occurring due to the position of the sun in the sky. He often stands a cartridge up on the bench and says that POI will follow the direction of the shadow cast from the cartridge (left in the mornings, right in the afternoons). He also quotes the adage "lights up, sights up" fairly often.

Is this what you're talking about in saying light's effect on iron sights being improperly applied to a scope? I always thought he was suggesting that it was due to the angle of the light on the target, but now, after hearing it related to the front post of an iron sight, it makes a more sense.
 
Re: Wind effects at 100yds?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: boudin</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">What you are doing is overlaying the effect of light as seen on Iron Sights and acting like it is effecting a scoped rifle... I have thousands of rounds in every kind of light condition and I have never see an impact change because of it.

On a 3D object light will change the angle of attack, on a 2D object like a reticle in a scope which is not being adversing effected by light as it is covered. Parallax would be a better explanation for shifts, before light would.

Mirage, been there done that got the t shirt, shooting in over 100 degrees in South Texas teaches you a thing or two about mirage and light... light is a non-issue with a scope. Irons, different animal, yes. </div></div>
Frank, this is something I have been trying to wrap my head around.

The range officer at my local spot has made mention several times of horizontal shift from the morning to the afternoon occurring due to the position of the sun in the sky. He often stands a cartridge up on the bench and says that POI will follow the direction of the shadow cast from the cartridge (left in the mornings, right in the afternoons). He also quotes the adage "lights up, sights up" fairly often.

Is this what you're talking about in saying light's effect on iron sights being improperly applied to a scope? I always thought he was suggesting that it was due to the angle of the light on the target, but now, after hearing it related to the front post of an iron sight, it makes a more sense. </div></div>

exactly ...

Lights Up, Sights Up is for Iron Sights... not scopes.

A reticle can be considered 2D as opposed to his 3D cartridge in the sun... You can't have the sun moving around the reticle changing the look. 1., it's covered by the scope tube, and 2, it's essentially flat.

This is the hold over from by gone days of Iron Sights, unless you are an Iron Sight shooter.

If what he is saying is to hold true, an Aimpoint red dot wouldn't work, it's essentially a parallax free system and where ever the dot is, if the scope is zeroed the bullet goes. When you remove the parallax from a Day Optic with a reticle, same thing... only if the user is just "focusing" the image picture and not removing the parallax will you see a shift and mistakenly then will probably say, "the image is in focus" which is not the same as removing the parallax.

3D objects in the sun will change perspective in the light, move the light change the perspective to the object... Lights Up Sights Up... take a scope and it is not the same.

The only way it will change your image is if the sun is pointing into the scope and causing you to magnify the problem 10x, 15, 20x times which will then effect your eyes... I just drape my now famous Shemagh over my head and most of my scope and sun / light problem is gone. If your getting what looks like lens flare in your scope chances are you looking into the sun... add a sunshade of use a ARD to cut the light down because your magnifying it into your eye ball, but you are not changing the perspective of the reticle.

How does ink on a piece of paper change perspective in the sun ? Especially with a magnified optic ?
 
Re: Wind effects at 100yds?

Roger. That makes perfect sense, thanks for the explanation.

The added bit about actually <span style="text-decoration: underline">removing the parallax</span> vs just focusing the target is especially helpful as I just switched from the 3-9 SS to the 5-20 SS, my first parallax-adjustable optic.
 
Re: Wind effects at 100yds?

Focus is not parallax, it is possible to have a perfectly focused target image and to have parallax present in the scope. Simply focusing, which 90% of the shooters do, is not correct and will cause a shift in impact. So while the image is in focus the reticle will float and not go where the shooter intends.
 
Re: Wind effects at 100yds?

This has always been something I wanted to look into more.
I experienced some goofy things going on with lighting at a match. The firing location was dark (very shaded). Firing from one mountain to another and it was miss after miss. Everyone was having trouble with it considering they were just smoking plates at the same distances at another location minutes before.
After picking up some splash I was able to get my partner on target with about a .8 call.
It didnt have anything to do with angle, temp, altitude, or weather conditions. All the normal basic things to take into consideration had been covered and addressed.
It was "that lighting thing" I had herd about but didn't know anything about it.
Sorry if this is drifting off topic a little from the OP but it just reminded me of something that still intrigued me.
 
Re: Wind effects at 100yds?

Lighting changes on targets effect the edges, not the center, all that can happen is a white target will reflect light blowing out the edges. So if you are ranging the target it will appear bigger. A black target will absorb the light, so the edges are tight and will appear smaller. light either bounces or absorbs.

A . 8 change in the mountains sounds like wind to me. A target is not going to move 3/4 M0A cause the sun was shining on it, but a mountain will change the wind that much. Multiple .75 times your distance and that is how far you think it moved.

Think about it, how does the center of a flat piece of steel move. You aim for the center quartering the target. If the center of target isn't moving 3/4 MOA.
 
Re: Wind effects at 100yds?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Muskett</div><div class="ubbcode-body">
There is one thing shooting a group and another to get it into the centre of the target. Just see how many groups posted aren't anywhere near the aiming mark!

</div></div>

Depends on what they were trying to accomplish first. When shooting for "group" I often dial the scope off at least one inch or so so I don't shoot out my aim point. Once one is able to extablish a group, dialing it into the target "center" is the easiest part.
 
Re: Wind effects at 100yds?

I agree with nearly everything said. This is a 100m thread but its difficult not to jump to 1000m conditions too.

I began shooting with iron sights and did a good 10 years of it with rifle and pistol before going to optics.

Certainly shooting pistol over open sights, even at close range, where the sun is in the morning, mid day and evenings there is a marked change of POI; can be a couple of inches. We gave ourselves different POAs. With rifles, probably because of the longer sight picture, it was less of an issue if I remember rightly.

On scopes, with low magnification, then I found that many shooters would push into a bright target. Nothing to do with the scope but all to do with the shooter. Having time to do a quartering double check will overcome this but not all targets are so accommodating. Here I'm being a bit unfair as when you have the time you can do checks.

I don't know why but some ranges with large hill backstops can get some real odd eddies, wind swirls, or something. We had a range that with both 5.56 and 7.62 would put everyone a foot high... well a lot. Some of it might be put down to the angle but not by that much. We gave up shooting beyond 200m on it and never worked out the real reason. Odd things happen.

I've dialed off for the same reasons in the past too. However, when able, I quite like going for the first round hole. Everyones favorite target has to be the preverbal spotting disc.
 
Re: Wind effects at 100yds?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Muskett</div><div class="ubbcode-body">

I don't know why but some ranges with large hill backstops can get some real odd eddies, wind swirls, or something.
</div></div>

My club range has not only a large hill backstop but there is a 25 foot rise from the firing line to the 300 yard targets. Both the 200 and 300 yard targets are on a terrace, one side shielded by trees and the other wide open to the winds. To make matters even worse, there are a series of overhead baffles that are designed to keep rounds from landing in nearby housing developments. If the wind is blowing over 2-3 MPH just plan on lots of swirling winds. Put out half a dozen wind flags and none will show wind from the same direction or even similar speeds. Just wait for a lull in the wind and then shoot like hell.
 
Re: Wind effects at 100yds?

My range has 20' berms on all three sides except the shooting area obviously and I have been noticing a lot of crazy winds at different times. The one thing I always see is an updraft near the targets holders which I imagine is caused by the berm behind it.