The Accurate Reloading Forums THE ACCURATE RELOADING.COM FORUMS Rifles Long Range Shooting Which Kestrell do you prefer?Go | New | Find | Notify | Tools | Reply | |
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Besides which Kestrell you prefer, is the Kestrell 4500NV with applied ballistics worth getting? | ||
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I have used a variety of anemometers, but I find a spotting scope is far more useful for estimating wind. I still use and anemometer, but rely more on mirage; the drift is almost never what an anemometer would predict. For ballistics, I use the BR2. I used to use a separate hand held device, but that is painfully slow. IMO, get a cheap anemometer and get a BR2. | |||
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AAZW, how do you estimate wind speed with a spotting scope? I've been concerned that the hand held devices would be too slow and that the BR2 would be the way to go...but they cost $1600.00. Do you know someone, who'd like to sell a BR2? | |||
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You watch the mirage. You need a good scope. In dry conditions like Arizona, I almost always have to focus between me and the target. I move the focus to a point between me and the target and then I can see the mirage moving. You need to practice a lot so that you can estimate wind. Yesterday I was shooting at 800 yards. Wind was very gusty and I remember thinking anyone who would claim they could shoot ethically in this condition is either a liar or a dreamer. I did better than expected, but still missed one shot by about 2.5 MOA left (300 RUM). My Edge was better, but even with that I missed one shot 8 inches right. My wind holdoff varied from 3 to 5 MOA. At times it would die (you could see the mirage boil instead of drift), then it would blast so hard my spotting scope would move. I also have a wind flag on my scope (on a shock cord). When I measure the wind or estimate it with mirage, I note the angle of my flag, which I can see peripherally when shooting. Certainly doesn't account for what is going on downrange, but better than nothing. It would have been a lot better to have a spotter to call the wind; I could see a slight mirage in my Nightforce, but not well enough to see the wind drift. BTW, my anemometer never went above 7.5 mph and I don't think I shot in wind over 5 mph. But the total effect was a lot more than that. One technique you may want to consider is a "rock shot." I am guessing a shot at long range is not going to spook game. Find a rock face with an aiming spot and shoot. Measure the difference with windage dots and shoot again. Normally you will hit within inches. One other thing: normally when you are hunting you are behind a hill, in a gulley, etc. and you are not "in the wind." Consequently, you can really blow it. The other thing i have noticed is that wind in the mountains/hills can give you some unexpected vertical impacts. It isn't as easy as TV. I love this subject and would appreciate other's observations and techniques. | |||
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Thanks for the feedback. You should spend the 20 USD and get the iphone app "Ballistic/Advanced". It's based on the JBM ballistic engine. The advanced wind dopping options are incredible. | |||
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I have a Kestrell in 3500, 4000, and 4500. I use the 3500 almost exclusively. _____________________________________________________ A 9mm may expand to a larger diameter, but a 45 ain't going to shrink Men occasionally stumble over the truth, but most of them pick themselves up and hurry off as if nothing had happened. - Winston Churchill | |||
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I use JBM ballistics; I like the spin drift calcs, which have to be considered at long range. But at the end of the day, skill at reading the wind is 99%; the tool you use is 1% - there is nothing available that lets you measure the wind and shoot. And if it did, at some point TOF becomes so long a gusting wind will prove to be too much. | |||
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How much spin drift do you use with the 300 SMK? _____________________________________________________ A 9mm may expand to a larger diameter, but a 45 ain't going to shrink Men occasionally stumble over the truth, but most of them pick themselves up and hurry off as if nothing had happened. - Winston Churchill | |||
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The iphone Ballistic App will calculate the spin drift component for you with the 300 SMK. | |||
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I use exbal on my computer. I was interested in what Arizona writer used for spin drift. I don not use any spin drift with that bullet and I know other top long range shooters that do not use spin drift with the 300 SMK. IMHO I agree with Perry Systems that spin drift needs to be shot to be determined correctly. _____________________________________________________ A 9mm may expand to a larger diameter, but a 45 ain't going to shrink Men occasionally stumble over the truth, but most of them pick themselves up and hurry off as if nothing had happened. - Winston Churchill | |||
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According to JBM, spin drift on a 300 Berger Elite Hunter is .5 MOA at 800 yards. This isn't much, but if you ignore it, you will miss. I shoot at least once a week at that range, almost always in the wind. I keep careful records of every shot. I have noticed my drift on wind from the left is always more than the same wind from the right. So if your drift without spin drift is 1.5, it is 2 MOA on a left to right wind, and 1.0 on a right to left wind. Measuring the absolute effect of spin drift is almost impossible, since you can never be sure the wind is zero at long range. Brian Litz set up an experiment in which he took two identical rifles, one with a right twist and one with a left twist, and shot groups at 1000 yards, alternating between them. The result was two distinct groups; the distance between them is twice the spin drift. If you zeroed at 1000 yards, then you wouldn't see it, but you would be slightly left at 500 yards (not a lot - 2 inches). Based on the JBM software, it seems bullets with a lower BC and higher velocity have more spin drift than bullets with higher BCs but launched slower. | |||
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AAZW, You mentioned that you are fascinated by the long range shooting and all it's facets and I share that feeling. Admittedly not as sophisticated in doing so as you are, but have sent many a round down range to 1000yds. in Long Range match shooting. All of my 1000yd shooting has been with micrometer sights at target faces and using official target faces with 44" black bulls eye(X ring some 10" in diameter) and the elevation is the easy part for the "come ups" are well known for calibers such as 308, 300 Win.Mag, but the impact of wind is the tricky part. Again, with "irons" the light has a lot to do with it as well for over a span of some 3/5ths of a mile cloud cover, shade, etc. plays tricks on your eyes. I also use the mirage for part of my ability to "read" the wind and do so at some 1/3rd. to 1/2 of the distance by back focusing the spotting scope to pick it up. I was taught to set your wind adjustment for that distance since the bullet first experiences the wind as it leaves the muzzle and it's course is impacted there the most. Some argue that is not the way to do it, but works for me. Would point out that using right hand twist barrel, most are, and right to left wind, that bullet will climb or lift and even though I have read the wind correctly and true elevation, if I do not alter elevation, usually a minute of angle-10" at 1000yds., the shot will stray into the upper right hand quadrant of the target. In short, will take you from an X or 10 at 2 o'clock to an 8 or even 7 ring. Wind left to right, just the opposite. I certainly don't discount the use of electronic devices, programs, etc. for long range shooting, but for matches, no electronic devices are permitted on the firing line. Some years ago at Camp Perry a young, new shooter was my assigned shooting partner and he had a lap top with him and did lot of calculations for each of his shots and was upset that the bullet did not go where he had determined. I politely explained to him that a calculator/lap top was not allowed, but go ahead and shoot anyway for did not figure he was going to win or even place in the match. After he shot his 20rnds. and my "turn in the barrel" he began instructing me on elevation, wind, etc. and my response to him was somewhat less polite, not rude, but firm. I shot a score of 196 w/ 8 X's and for me that was a good score, but others shot much better. Young man was somewhat upset that he had not done well, but explained to him that there is simply no substitute for "time behind the gun." For my type of long range shooting I find the use of scope/optics no advantage since I am in prone, mat, sling position and the scope only magnifies the small movements and hard for me to control. Movement is there with irons as well but not so obvious which gives me problems in holding. Not for me, but if shooting at game there is no question using a scope would be the way to go, but with steadiest position or rest that you could fine to make a humane kill. I enjoy reading your postings of long range shooting. | |||
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In my experience all bullets do. Or show enough spin drift to worry about. At 1006 I have no trouble hitting my 12" circle gong with no spin drift with the 300 SMK out of my 338 Laupa. Perry systems say that Bergers are notorious for spin drift. _____________________________________________________ A 9mm may expand to a larger diameter, but a 45 ain't going to shrink Men occasionally stumble over the truth, but most of them pick themselves up and hurry off as if nothing had happened. - Winston Churchill | |||
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Very informative; I am trying to calculate "rules of thumb" for the vertical component of wind. Don't have my log handy, but I think about 1 click per five mile of wind at 800 yds is about right, but I notice JBM doesn't account for this. I don't know the physical effect, but it seems like the rifling "bites up" into a wind from the right and "bites down" in a wind from the left. I would add I shoot in open terrain except for my Friday morning gong shoots at 500 yards, which is on a range. In open terrain, over rolling hills and draws, I notice strong winds also produce downdrafts and updrafts that sometimes give very unpredictable results, often greater than the impact of the up/down effects of left/right wind. | |||
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Using your term "bite" in the wind developing upward or downward impact on the bullet is basically what I was trying to describe. Having never used left hand rifling would have to assume the results would be the opposite?? A situation I always watch for are "boils" in the mirage and have been taught to not shoot in those conditions for it will cause the flight of the bullet to climb. Have experimented with it and bullet will impact higher than I had anticipated. Can't say that I totally ignore the wind flags at a range, but for me they are not a good indicator of small wind changes that can work against you. Much prefer to observe leaves, grass, small limbs, wind on my face, etc. and of course the mirage. The mirage image I see in the spotting scope does little to tell me of the direction of the wind, but if having observed it for a while and see as flowing like a river at the target face, and then it does not reveal itself in the scope, that tells me it has "flat lined" and good indication that the wind speed is at or near 10mph or more. Calibers I have experience with are 308,'06 and 300Win.Mag. and very old formula for predicting wind drift of the bullet developed my U.S.Army with the advent of the 30-06Gov't is to multiply the Range x Wind Velocity and divide by 1000 to give adjustment in a full value wind, either 9 o'clock or 3 o'clock. Range say at 800yds x est. wind velocity of 10mph would yield 8000/1000 equaling 8 moa of adjustment either right or left. Speed of wind easier for me to judge than direction and if not full value would use a different divisor for an answer, but I simply take something on the order of 60% of a full value number and it works pretty well for me. In the example instead of 8moa adjustment, would take 4.8moa or very near that since the true direction of the wind is unknown. In situations where you must take the shot, some matches you do not get sight in shots, this approach will normally get you on the target face and then you are off and running. Just a suggestion. | |||
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