quote:

Originally posted by MFD:
Hello Another AZ Writer,
Well, not sure I understand your thinking that a wind from either 6 or 12 o'clock directions would have far more impact on the flight of the bullet than one from the 3 or 9 o'clock directions?? The 3 and 9 is considered "full value" winds as opposed to other directions or 1/2 or even 1/4 value. Checking on dope sheets, wind charts, etc. the adjustment required for other than 3 or 9 are less which would indicate less impact than more.

MFD:

Here is the why a tail wind is a killer.
On a clock face, a wind from 7 o’clock is blowing at a 33 degree angle; 8 o’clock is 66, and 9 o’clock is 90 degrees. So 6:30 is half 33 or 16.5 degrees. Let’s say the wind blows from 5:30 to 6:30 (that would feel like it was blowing from behind you); we are shooting a .7 BC bullet at 2800 fps. At 900 yards the drift in a 5 mph wind is 13 inches. At 5:30 the angle is 16.5 which has a full effect of 28.8%. Failure to read this wind puts your bullet 3.7 inches left. Two minutes later the wind goes to 6:30; another 28.8% full effect wind but now the bullet hits 3.7 inches right. Total error caused by the shift in wind is 7.4 inches.

Now consider the same wind but from 8:30 to 9:30. The full effect of a wind from 8:30 is 96% of full value. At 9:30 it is the same: 96% of full value. So the most our bullet will blow is from 96 to 100 percent full value, which is 12.5 inches to 13. Granted, the total wind deflection is not greater, so you do have to be able to calculate the proper deflection, but the effect of a shift in wind plus or minus 16.5 degrees around 9 o’clock is far less than the effect of the same variation in direction around 6 pm (or for that matter 12 o’clock). In fact, it is 15 times greater than a wind shifting around 9 o'clock.

My gunsmith shoots 1000 yard competition and always felt winds from behind were evil, but once I explained the math it was an “aha” moment for him.

Hello AnotherAZWriter,
Well, you lost me about the third sentence. Shooting the Palma Match- 8,9,1000yds, must be 308 and iron sights, sling/mat- at Perry some years ago the shooter I was teamed up with had with him his pocket calculater(that is illegal for no electronic devices on the firing range for competitors)and when he handed me his score book noticed that he was classified as a Sharpshooter. Cautioned him that if the RO saw the calculator he would make him leave the line or give up his device. Also had a electronic wind meter device, but told him I did not care and just advising him of the possible consequences. Prior to each shot he would enter supposed data which he had calculated seemingly for all possiblities due to conditions and the ballistics of the 308 and adjust his Warner sight( he had quality equipment.) Believe they gave us up to 5 sighters at the 800 line and 2 sighters for the next two stages. Well, he did not get on target for his first 5 sighters and you have 15 minutes for 15 record shots. Report from pits came back that "he was in the dirt" and that becomes a safety factor. I looked away from my spotting scope and the RO was standing there looking down at the various devices and told me to tell him to put them away or leave the line. You are not allowed to coach the shooter when you are scoring, but you can call out his hits if he has any and the RO also told me to go ahead and give him some elevation/windage dope and get him on target ( the clock is tick'n.)
Knelt down beside him and gave him some elevation and windage and he got on target, but was absolutely destroyed that his calculator and his shooting were not in the same spot on the planet. Got him on target next shot and he proceeded to shoot couple more misses and rest were mostly 7's and 8's. We went to pits together and absolutely positive that he had done the math wrong. The 9 and 1000 yard targets were pretty much the same, not pretty, and after the match riding back to the hut area he said he was going to recalculate the ballistics that eve. and would do much better at the two remaining 1000yd matches. He did not do better and I was not with him the other two, but knew the ones that were and they both gave up on him and let him fling away with poor scores. Bottom line is that the fellow had not spent enough time behind the gun and simply could not shoot. In this type of competitive shooting the mechanics, knowledge, equipment is in reality a small part of the results. Primary influence on good or bad scores/hits is the "trigger puller." This took place sometime in the mid 90's and as fate would have it he showed up at Oak Ridge around 2003 and he recognized me and handed me his score book and noticed he had a Master Classification Long Range. I congratulated him for his progress and he just smiled and said he finally threw away his calculator, practiced and learned to shoot. Whether it is the math or whatever, if it helps you be a better shooter, that is what counts. Favor center and squeeze the trigger and pray the target goes down! If it does, you are off to the races.

MFD:

I never shot the Palma. But I was the US Army Alaska undefeated champion for three years in a row. I competed twice in the I Corps Championships and finished 1st and 2nd (that was the competition for the best shot in the western US, about 50,000 troops at that time). The time I won the I Corp championship LTG Norman Schwartzkopf gave me my trophy (he was the CG). When I finished second I distinctly remember losing by only a few points to a Ranger sniper.

Never did use a calculator or anemometer.

AnotherAZWriter,
That is quite an accomplishment and one to be proud of for sure. At local range we conduct National Match shoots and simulated long range matches monthly and I serve as sort of a coach/line officer with emphasis on new shooters, be they young or old. Over the years we have had quite a few youngsters show up and get "hooked" on the shooting sports and in lots of cases has actually turned their life around.
The discipline, effort, dedication it takes to become skilled develops into a person who prior to the experience had no discipline or dedication to anything other than the cell phone or standing on the street corner. Several of the young shooters have went on to school and become Doctors, Teachers, CPA's and yes, even Lawyers. Our small bore group annually funds trips to Camp Perry for the young shooters and often parents tell us that they are amazed at the change in overall attitude shown by their children in just a year or so of competing. Those that have participated in the smallbore shoots eventually come to the HighPower matches and their previous experience/training is obvious and they can definitely "show up" some of the old timers there. Be it short range, long range, smallbore or HighPower, it is a sport that needs to be suported whenever possible.

Thanks for the kind words MFD. There is absolutely no substitute for competitive shooting. Those who say "he only shoots at targets" haven't got a clue - and certainly have never toed the firing line waiting for the targets to come up. I am guessing I have shot a wider variety of stuff than any other poster on the LR board and will be the first to say that competitive shooters are a breed unto themselves. Those who say it isn't hunting are correct: it is a lot harder.

quote:

Gerald Peryy feels that spin drift needs to be measured by shooting to 600 yards on a windless day and measuring the POI VS POA and imputing it in the spin drift feature on Exball

Just wondering, where do you find such days? Even just a mild mirage effect will induce a POI/POA error. I don't think there is such a thing-windless day that is, air ia always moving in some vector, all of which influence bullet fall.

Spin and corialis effects, I think, are nuances that are best accepted as facts and added to the overall equation for the most part. I am not certain any shooter in the open can determine it's shot to shot influence, as there are too many other variable in light and atmosphere to allow isolation.

Could be wrong, but I don't really think so.

quote:

Originally posted by Andrew cempa:

quote:

Gerald Peryy feels that spin drift needs to be measured by shooting to 600 yards on a windless day and measuring the POI VS POA and imputing it in the spin drift feature on Exball

Just wondering, where do you find such days? Even just a mild mirage effect will induce a POI/POA error. I don't think there is such a thing-windless day that is, air ia always moving in some vector, all of which influence bullet fall.

Spin and corialis effects, I think, are nuances that are best accepted as facts and added to the overall equation for the most part. I am not certain any shooter in the open can determine it's shot to shot influence, as there are too many other variable in light and atmosphere to allow isolation.

Could be wrong, but I don't really think so.

Come on Andrew; you just input everything into a PDA and fire away. Death at 1000 yards every time.

There are so many things we can't measure that at some point it does become too far to shoot at game. At some point there is no room for error, and unfortunately, the longer the range, the less the allowable error. After all, no rifle shoots one hole groups at 1000 yards.

Good points on this thread guys.
Out of interest, are there any statistics on the number of first shot kills made by snipers, they do it for a living after all, at 800yds plus?

Seems to me that shooting at long range is a tricky business without being able to shoot groups and use sighters.

quote:

Originally posted by Ghubert:
Good points on this thread guys.
Out of interest, are there any statistics on the number of first shot kills made by snipers, they do it for a living after all, at 800yds plus?

Seems to me that shooting at long range is a tricky business without being able to shoot groups and use sighters.

Back when I was in the Army Delta Force snipers had to hit a man sized target 100% of the time at 600 yards and 90% at 1000 yards. But I don't know under what conditions. I would also add the standard "man size" target is a lot wider than the typical man, and a lot wider than the vital area of a deer or antelope.

The often repeated story of the longest sniper shot fails to acknowledge the fact that guy missed quite a few times before he connected.

Finally, don't forget snipers don't act alone: there is a shooter and a spotter. The fact the spotter is the better shot ought to tell you something right there: calling the windage is the most important element to connecting.