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Wow! I'm excited now. Big stick will be along to straighten out the kouch Kunitz out. LMAO
Take care, Willie
Cry to the heavens and let slip the dogs of war. For they must feed on the bones of tyranny. In order for men to have freedom and liberty.
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Campfire 'Bwana
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Campfire 'Bwana
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Hey fred, "formillous" posted this thread because a few people asked him to. Not everyone was born with a mil taped to their forehead.
A wise man is frequently humbled.
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Someone said it ain't hard to tell who shoots. Fredrica just is dying to have others put him in the shooters category. TFF
Take care, Willie
Cry to the heavens and let slip the dogs of war. For they must feed on the bones of tyranny. In order for men to have freedom and liberty.
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You're right about the calculations, though RH does affect a ballistic solution, because it changes the effective density of the air, regardless of air pressure. Water vapour molecules are actually lighter and less dense than air molecules, so high RH decreases the air density. The effect of RH on air density is minimal, though, compared to pressure and temperature.
The way DA simplifies things, is that there are devices that use sensors to take the measurements and spit out a DA number for you to enter into your ballistic app. That way you don't have to manually take 4 measurements and enter each in separately. If your ballistic app is equipped with on-board sensors to take all necessary measurements, then it doesn't matter which air density calculation standard you use, except that you need to remember that the fewer measurements you can take, the better, as each measurement introduces error into the calculation. So measuring absolute/station pressure directly is better than taking a barometric pressure measurement and then calculating the station pressure using a temperature and altitude measurement.
Right, I agree that RH affects air density. That is why I am not confident that station pressure fails to account for it, but again I’d have to go to some references. This is not a thing I’ve had occasion to calculate, at least not for a long while. Talking about the calcs was my attempt to make sure we don’t assume either too much or too little about one another’s thinking. My point is that the maximum number of measurements one needs to make and possibly enter is two: station pressure and perhaps RH. If the ballistic solver is forcing entry of temp and alt on top of station pressure, then it’s programmers may be ignorant of what is needed to properly compute the solution(?). DA _may_ simplify that by one item. However, it looks very much like trying to work around an elaborate set of work-around a that we’re already used to using, that most don’t understand we don’t need to bother with. Just use station pressure and _maybe_ RH and be done. No more equipment to buy, no more elaborate gobbledygook that wows is with technical nonsense that, in the end, just makes a ton of calculations in one direction merely so that the same calcs can be run the other way before spitting out an answer. To me, entering 1 or 2 parameters and dropping the pretense is much simpler and easier than entering for sure only 1, but requiring yet more equipment or calculations and reference tables. Perhaps we all have our own notions of what constitutes simplicity and ease.
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You're right about the calculations, though RH does affect a ballistic solution, because it changes the effective density of the air, regardless of air pressure. Water vapour molecules are actually lighter and less dense than air molecules, so high RH decreases the air density. The effect of RH on air density is minimal, though, compared to pressure and temperature.
The way DA simplifies things, is that there are devices that use sensors to take the measurements and spit out a DA number for you to enter into your ballistic app. That way you don't have to manually take 4 measurements and enter each in separately. If your ballistic app is equipped with on-board sensors to take all necessary measurements, then it doesn't matter which air density calculation standard you use, except that you need to remember that the fewer measurements you can take, the better, as each measurement introduces error into the calculation. So measuring absolute/station pressure directly is better than taking a barometric pressure measurement and then calculating the station pressure using a temperature and altitude measurement.
Right, I agree that RH affects air density. That is why I am not confident that station pressure fails to account for it, but again I’d have to go to some references. This is not a thing I’ve had occasion to calculate, at least not for a long while. Talking about the calcs was my attempt to make sure we don’t assume either too much or too little about one another’s thinking. My point is that the maximum number of measurements one needs to make and possibly enter is two: station pressure and perhaps RH. If the ballistic solver is forcing entry of temp and alt on top of station pressure, then it’s programmers may be ignorant of what is needed to properly compute the solution(?). DA _may_ simplify that by one item. However, it looks very much like trying to work around an elaborate set of work-around a that we’re already used to using, that most don’t understand we don’t need to bother with. Just use station pressure and _maybe_ RH and be done. No more equipment to buy, no more elaborate gobbledygook that wows is with technical nonsense that, in the end, just makes a ton of calculations in one direction merely so that the same calcs can be run the other way before spitting out an answer. To me, entering 1 or 2 parameters and dropping the pretense is much simpler and easier than entering for sure only 1, but requiring yet more equipment or calculations and reference tables. Perhaps we all have our own notions of what constitutes simplicity and ease. Gotcha. I misunderstood you there- thought you were questioning whether RH is relevant or not. My thinking is, given that a pressure gauge measures the absolute pressure of the air at the position of the gauge, it's really just measuring the weight of the air column over a given area, and that weight includes the weight of the air molecules as well as the water vapor molecules. So station pressure does account for RH, but air density is calculated by inputting measured absolute pressure, RH, as well as temperature, which is why those variables appear in all the top ballistic apps. So we can input 3 variables- absolute pressure, RH, and temp, we can enter 4 variables- baro pressure, altitude, RH, and temp, or 2 variables- DA and temp. I agree. It doesn't matter which method you use. It just saves time and complication in the field if you're required to enter fewer inputs. I'm not saying one way is better than the other as long as the process and inputs are simplified and minimized. I've always used abs. pressure, temp, and RH method up until now, because my Kestrel doesn't measure DA and my phone has an integrated pressure sensor, but now that I have that DA app, I may start using that. We'll see. Really, I'm either entering DA and temp, or abs. pressure and temp. I leave RH set at 50% unless I'm shooting beyond 1000, given how little impact it has on the shot solution.
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Yea, I also flunked spelling in shcool..thanks for the reminder..
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The SWFA really is a no brainer to sight in. Shot one at 100, used the reticle to see I was off 1.2 vertically and 1.5 horizontally. 12 clicks over and 15 up. Next shot right on.
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So we can input 3 variables- absolute pressure, RH, and temp, we can enter 4 variables- baro pressure, altitude, RH, and temp, or 2 variables- DA and temp.
I agree. It doesn't matter which method you use. It just saves time and complication in the field if you're required to enter fewer inputs. I'm not saying one way is better than the other as long as the process and inputs are simplified and minimized. I've always used abs. pressure, temp, and RH method up until now, because my Kestrel doesn't measure DA and my phone has an integrated pressure sensor, but now that I have that DA app, I may start using that. We'll see. Really, I'm either entering DA and temp, or abs. pressure and temp. I leave RH set at 50% unless I'm shooting beyond 1000, given how little impact it has on the shot solution.
Actually if you use DA, you shouldn't need to enter temp, because it's already part of the DA calculation. Ballistic AE does still ask for temp, but it's only for converting velocity to a mach number, I think for estimating the transonic region. Changing the temp value with a consistent DA input shouldn't have any effect on the drop values, if I understand what Ballistic AE is doing.
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Side note for those still stuck on inches and the odd 1 mil = .36" per 100 yd thing - it's really just .1 yd at 100 yd. There happens to be 36 inches in a yard...
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So we can input 3 variables- absolute pressure, RH, and temp, we can enter 4 variables- baro pressure, altitude, RH, and temp, or 2 variables- DA and temp.
I agree. It doesn't matter which method you use. It just saves time and complication in the field if you're required to enter fewer inputs. I'm not saying one way is better than the other as long as the process and inputs are simplified and minimized. I've always used abs. pressure, temp, and RH method up until now, because my Kestrel doesn't measure DA and my phone has an integrated pressure sensor, but now that I have that DA app, I may start using that. We'll see. Really, I'm either entering DA and temp, or abs. pressure and temp. I leave RH set at 50% unless I'm shooting beyond 1000, given how little impact it has on the shot solution.
Actually if you use DA, you shouldn't need to enter temp, because it's already part of the DA calculation. Ballistic AE does still ask for temp, but it's only for converting velocity to a mach number, I think for estimating the transonic region. Changing the temp value with a consistent DA input shouldn't have any effect on the drop values, if I understand what Ballistic AE is doing. Yeah, I noticed that. I suppose if you don't care about the transonic region you could leave the mach number/temp out and just use the DA input.
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Hey fred, "formillous" posted this thread because a few people asked him to. Not everyone was born with a mil taped to their forehead. Smoke everyone here could learn a bunch from formillous just fun that it’s needed to explain the most simple aspects of reticle use. It was in no way a shot at him but the guys that requested crack me up.
Last edited by fredIII; 12/09/17.
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Actually if you use DA, you shouldn't need to enter temp, because it's already part of the DA calculation.
So, Yondering, do you know: Since RH impacts air density, doesn't station (absolute) pressure account for it, and thus the only thing the ballistic solver needs is station pressure?
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Campfire 'Bwana
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Campfire 'Bwana
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Hey fred, "formillous" posted this thread because a few people asked him to. Not everyone was born with a mil taped to their forehead. Smoke everyone here could learn a bunch from formillous just fun that it’s needed to explain the most simple aspects of reticle use. It was in no way a shot at him but the guys that requested crack me up. I myself, crack myself up. That's all I need.
A wise man is frequently humbled.
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Ping pong balls for the win. Once you've wrestled everything else in life is easy. Dan Gable I keep my circle small, I’d rather have 4 quarters than 100 pennies.
Ain’t easy havin pals.
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Campfire 'Bwana
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Campfire 'Bwana
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"I can't be canceled, because, I don't give a fuuck!" --- Kid Rock 2022
Holocaust Deniers, the ultimate perverted dipchits: Bristoe, TheRealHawkeye, stophel, Ghostinthemachine, anyone else?
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Actually if you use DA, you shouldn't need to enter temp, because it's already part of the DA calculation.
So, Yondering, do you know: Since RH impacts air density, doesn't station (absolute) pressure account for it, and thus the only thing the ballistic solver needs is station pressure? I don't claim to be an expert on this stuff, but I'm pretty sure station pressure by itself doesn't account for everything, and also that temperature is much more significant than RH. All of the Density Altitude calculators I've seen use station pressure, air temp, and either dew point or RH and elevation to perform the calculation. I believe the station pressure itself is not enough info, because a compressible gas (like air) changes pressure and volume with temperature. Thermodynamics wasn't my strongest subject, but I think the takeaway here is that we can have a taller but less dense column of air that creates the same absolute pressure but with less density due to higher temp. Clear as mud? The short answer is that even in it's most simplified form, air density is at least a 3-dimensional problem of pressure, temperature, and one or more other variables. Here's a good link that explains density altitude in far more depth than you probably want, but it also has a few DA calculators using different methods: http://wahiduddin.net/calc/density_altitude.htm
Last edited by Yondering; 12/09/17.
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As much as I'd maybe like to, I can't get MIL going and I'm stuck on MOA. Me too....and one of the primary reasons is I'd have too much crap to switch over. Are you guys still thinking in terms of inches of correction to make? Nope. I just have a bunch of stuff memorized and I'd also have to switch a bunch of scopes. Example -- I have three 223's that I shoot (2 bolts, one AR). I know this one's up 24 (MOA) at 800, that one is up 10 at 500, one is up 6 at 400, etc. Each has a chart too, but they're almost useless at this point. About the only time I use the chart is for wind. Throw 5-6 more rifles into the mix and that's a bunch of scope purging and a ton of time (money too!). I typically choose one bullet for each rifle and stick with it. If I added a different cartridge to the line up and scoped it with a mil set up, it probably wouldn't bother me. I'm just using numbers anyway - not inches.
I enjoy handguns and I really like shotguns,...but I love rifles!
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- Greg
Success is found at the intersection of planning, hard work, and stubbornness.
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This is generally what happens within a day or two when die hard MOA users learn to use both MOA and mils correctly-
"Wow both are just numbers that I spin to and they both work the same"
and then
"Wow, you know mils is easier to see and count on the reticle"
and then
"Wow, the drop corrections are easier to remember in mils"
and then
"Wow, wind brackets are easier with mils"
And then....
"I'm selling all my MOA scopes".
Seen't it. DOZENS of times. Thank God I don't have to change over. Maybe my lack of knowledge/involvement in the long range game previously, is to my advantage this time.
Mark
NRA Life Member Anytime anyone kicks cancers azz is a good day!
~Molɔ̀ːn Labé Skýla~
Oh The Drama!
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