Frontal wind, veritical poi change

[Luke45]

So this guy at the range kept saying that a wind at your back or front will "push" the bullet up or down. (That was his excuse for missing) I guess I never noticed enough difference?

Is this true? Extreame example, say 20 mph in your face or back at 1000 yards with 300 mag, what would the poi difference be if any?

My assumption is that unless the wind is angled up or down it won't make a difference other than the velocity of wind changing the perceived velocity of bullet which wouldn't be hardly anything.

Anybody?

[earl39]

I don't know about a 300wm but at 1000 yards it will do strange things to a 175mk from a 308win. Of course we shoot an a military range so the wind is going over 5 berms between us and the 1000 yard berm.

[Luke45]

I don't know about a 300wm but at 1000 yards it will do strange things to a 175mk from a 308win. Of course we shoot an a military range so the wind is going over 5 berms between us and the 1000 yard berm.

Did you see vertical shifts? I've only seen vertical shifts when shooting across canyon where the wind sweeps upward or is traveling down a hill

[sharpshooter]

A tailwind usually will not affect vertical as much as a headwind. A headwind will push bullet up at short range, and down at long range.

[earl39]

Did you see vertical shifts? I've only seen vertical shifts when shooting across canyon where the wind sweeps upward or is traveling down a hill
Yes there are shifts that can be attributed to the wind. POI is constant with wind blowing and as you break the shot the wind dies POI changes depending on wind speed you can drop 2 or 3 MOA. I can't speak to flat ground, as i said there are 5 berms the wind crosses between the firing line and the 1000 yard targets.

[stomp442]

Yes wind can and will make a big difference at long range. Even in only a 10mph head or tail wind a .300 win mag pushing the 185 vld at 3000 fps has a difference of over 3 inches vertical. Add to that any vertical value of wind over the course of trajectory and you start talking pretty big numbers. Also keep in mind that wind values are generally higher the higher the bullet travels along its trajectory. point being although the head or tail wind may be 10 mph at your position it may be 12 or 15 at the peak of the bullet trajectory where the bullet is the highest above the line of sight. Also bear in mind that even if you have a very low standard deviation of say 5 fps with your load you can potentially have 10 fps difference from shot to shot which compounds things even further. Shooting consistently at long range is no easy task and a miss even for a seasoned shooter and highly accurate equipment can be a attributed to a number of things.

[acemisser]

yes...head wind,bullet up
tail wind ,bullet down.....remember that..

[Cat 64]

[QUOTE=sharpshooter;277533]A tailwind usually will not affect vertical as much as a headwind. A headwind will push bullet up at short range, and down at long range.[/QUOTE

What is (in yards) short range and what is long range?

[Cat 64]

yes...head wind,bullet up
tail wind ,bullet down.....remember that..

any distance?

[sharpshooter]

Short range..100 yds, long range 200+. The only way to find out is to experience it. Things may differ depending on the rifle range.

[tufrthnails]

I was actually playing around with my scope calc earlier http://spoton.nikonsportoptics.com/spoton/spoton.html#Index:94 kinda fun to play with. So I fudged some data for you as simple example.
300 win mag, Fed 180 gr woodliegh weldcore sp, 3100 fps, 200 yrd zero, 1000 yrd target, dead 0 wind -356.64", head wind 10 mph -359.82, 20 mph -363.07", 30 mph -366.40, Tail wind 10mph -535.54, 20mph -350.5", 30 mph -347.52". Keep in mind this is just a calc and if you put the zero to 1000 yrd and target at 1000 yrd it will show 0 difference for head and tail wind.

[chukarmandoo]

I was actually playing around with my scope calc earlier http://spoton.nikonsportoptics.com/spoton/spoton.html#Index:94 kinda fun to play with. So I fudged some data for you as simple example.
300 win mag, Fed 180 gr woodliegh weldcore sp, 3100 fps, 200 yrd zero, 1000 yrd target, dead 0 wind -356.64", head wind 10 mph -359.82, 20 mph -363.07", 30 mph -366.40, Tail wind 10mph -535.54, 20mph -350.5", 30 mph -347.52". Keep in mind this is just a calc and if you put the zero to 1000 yrd and target at 1000 yrd it will show 0 difference for head and tail wind.

My app Shooter says no difference with head wind or tail wind. Only effect on bullet is side winds. So a up draft or down draft is the same as side wind.

[thermaler]

Hmmm..my pilot experience would say this: The actual bullet's indicated trajectory/speed DOES NOT change in a head or tail wind--but it's GROUND speed will. This is because the bullet is traveling in an air mass that is traveling itself. Since a target is on the ground at a fixed distance and the bullet does not have an engine to maintain velocity--it's drop (as a function of it's BC) would necessarily have to change relative to a ground target. The additional head or tailwind effect may be negligible depending upon the bullet's BC and "flying efficiency" and distance to target--but it's definitely there.

[thermaler]

An intriguing question--in the case of an aircraft maintaining constant airspeed the solution would be simply to add or subtract the head or tailwind to arrive at the groundspeed or "drop." But a bullet's trajectory "decay" is a complex thing to plot precisely--so it would not be simply a linear additive or subtractive function--I think!

[foxx]

[QUOTE=sharpshooter;277533]A tailwind usually will not affect vertical as much as a headwind. A headwind will push bullet up at short range, and down at long range.[/QUOTE

What is (in yards) short range and what is long range?

I don't know from experience, but I imagine as long as the bullet trajectory is still in an upward path, the headwind would push it up. Once it starts heading down, the headwind would push it down.

[sharpshooter]

[QUOTE=Cat 64;277810]

I don't know from experience, but I imagine as long as the bullet trajectory is still in an upward path, the headwind would push it up. Once it starts heading down, the headwind would push it down.

You are correct sir.

[eddiesindian]

What Ive seen when going out to 1K out in TX desert wide open terrain @ 4200ft elev. is that if the wind has been to my back, then it makes for a pretty sh**** shooting day. No consitancy to say the least. Ive sometimes found them to float high and adjust accordingly and hit paydirt only to be off again after about the 3 shot.
I agree withy stomp442.........even seasoned shooters get to eat humble.
What Ive found is that if I have winds from my back pushing 15-20.....I pack my rigg, set it back in my truck, and proceed to talk shop with fellow shooters.

[thermaler]

Ummmm--AFAIK a bullet does not "gain altitude" or go up--unless you point the muzzle that way. It's more or less a battle of gravity vs. velocity--which might help explain Deano's OCD behavior. ; )

[foxx]

Ummmm--AFAIK a bullet does not "gain altitude" or go up--unless you point the muzzle that way.

Right, but when shooting from the ground at a target positioned 100 yards away at roughly the same height as yourself, you ARE pointing the muzzle up, albeit only slightly. The barrel is pointed up so as to meet the level of the line of sight of the scope reticle. Usually,the higher the scope is mounted above the barrel, the greater the upward angle of the barrel. That is why , in most situations, the bullet is still rising out to about 150-175 yards. It's also why a bullet crosses the vertical line of sight 2x... once at very close range (20 yards?) , and again at longer range (200 yards?).

[thermaler]

Right, but when shooting from the ground at a target positioned 100 yards away at roughly the same height as yourself, you ARE pointing the muzzle up, albeit only slightly. The barrel is pointed up so as to meet the level of the line of sight of the scope reticle. Usually,the higher the scope is mounted above the barrel, the greater the upward angle of the barrel. That is why , in most situations, the bullet is still rising out to about 150-175 yards. It's also why a bullet crosses the vertical line of sight 2x... once at very close range (20 yards?) , and again at longer range (200 yards?).A much better explanation, thank you--I was responding to the notion that a bullet gains altitude in a headwind.