Range Report ..
- Thread starter cstmwrks
- Start date
Re: DC & ColdBore 1.0
I'm trying to figure this out for myself as well. I intend to shoot through my chronograph at 4 different distances to obtain the data needed for a calculation to get an idea what the calculated number should look like given the 115 DTAC or 208 AMAX I am shooting.
I was intending on doing this tomorrow out to 400. Starting with muzzle velocity, 100, 200, 300 and ending on 400. Any further than 500 and I risk hitting my screens due to entry angle on target and any wind effects. The window is small and I will use my infrared screens for best consistency.
I've played with the DC numbers to see how they affect solution output, but its not as I expected and I don't see enough change going one direction or another for it to make sense to me.
.500 is supposed to be a very close number when shooting a boat-tailed bullet design as that is the default as well.
Adjusting the DC number is akin to bending the drag curve, but its not jiving the way I would have thought.
ETA: for those that do not know; DC is <span style="font-weight: bold">D</span>rag <span style="font-weight: bold">C</span>oefficient. The solver in Coldbore goes about calculating the solution by referencing a different standard when calculating drag.
I assume it uses the input of the BC to aid in a portion of the calculation, but relies on the DC for an accurate prediction for ranges beyond 1000 yards.
This is a portion I am still unclear about and still trying to wrap my head around.
I'm trying to figure this out for myself as well. I intend to shoot through my chronograph at 4 different distances to obtain the data needed for a calculation to get an idea what the calculated number should look like given the 115 DTAC or 208 AMAX I am shooting.
I was intending on doing this tomorrow out to 400. Starting with muzzle velocity, 100, 200, 300 and ending on 400. Any further than 500 and I risk hitting my screens due to entry angle on target and any wind effects. The window is small and I will use my infrared screens for best consistency.
I've played with the DC numbers to see how they affect solution output, but its not as I expected and I don't see enough change going one direction or another for it to make sense to me.
.500 is supposed to be a very close number when shooting a boat-tailed bullet design as that is the default as well.
Adjusting the DC number is akin to bending the drag curve, but its not jiving the way I would have thought.
ETA: for those that do not know; DC is <span style="font-weight: bold">D</span>rag <span style="font-weight: bold">C</span>oefficient. The solver in Coldbore goes about calculating the solution by referencing a different standard when calculating drag.
I assume it uses the input of the BC to aid in a portion of the calculation, but relies on the DC for an accurate prediction for ranges beyond 1000 yards.
This is a portion I am still unclear about and still trying to wrap my head around.
Re: DC & ColdBore 1.0
The problem with this approach is the fact that you will be shooting a different round through each chrono, when what you need is the velocity decay. For this to really work, you need to shoot through all 4 chronos at the same time. Not very practical, not to mention the individual chrono errors. This only really works with a Doppler radar track, also not very practical.
Instead, using the nominal BC and average velocity, shoot the calculated come ups at 300, 800 and whatever range predicts about 1400-1200 fps at the target. Shoot 10 round groups, measure group center to POA.
If all 3 groups are off the POI in the same directon, adjust the BC value a bit, .010 is not too much, see how close you can get the 800 yard group to center. Tweaking the velocity average as much as 100 fps +/- is also fine, chronos are not known for their precision values.
ONLY when that is done, and you are still off at the longest range should you work the DK/DC value.
FFS has a tool to automatically iterate through the DK values, with CB you'll need to twiddle the value manually. If you are under the POI at the longest target, reduce the DK value in .005 steps, if you are over, increase it. It does not take much, 3 digits are signifigant. Get the LONG group as close to center as possible, it should end up within 1/2 a click value of center. Recheck your short and mid range values, they should remain within a click value as well.
Important note. This is all totally useless if you have not got the scope calibration correct, so you KNOW what you've dialed up and the ranges must be +/- a couple yards and +/- 5 degrees of slope. Ideally, each of the groups will be shot over a chrono, so you have the actual average velocity for that group.
The problem with this approach is the fact that you will be shooting a different round through each chrono, when what you need is the velocity decay. For this to really work, you need to shoot through all 4 chronos at the same time. Not very practical, not to mention the individual chrono errors. This only really works with a Doppler radar track, also not very practical.
Instead, using the nominal BC and average velocity, shoot the calculated come ups at 300, 800 and whatever range predicts about 1400-1200 fps at the target. Shoot 10 round groups, measure group center to POA.
If all 3 groups are off the POI in the same directon, adjust the BC value a bit, .010 is not too much, see how close you can get the 800 yard group to center. Tweaking the velocity average as much as 100 fps +/- is also fine, chronos are not known for their precision values.
ONLY when that is done, and you are still off at the longest range should you work the DK/DC value.
FFS has a tool to automatically iterate through the DK values, with CB you'll need to twiddle the value manually. If you are under the POI at the longest target, reduce the DK value in .005 steps, if you are over, increase it. It does not take much, 3 digits are signifigant. Get the LONG group as close to center as possible, it should end up within 1/2 a click value of center. Recheck your short and mid range values, they should remain within a click value as well.
Important note. This is all totally useless if you have not got the scope calibration correct, so you KNOW what you've dialed up and the ranges must be +/- a couple yards and +/- 5 degrees of slope. Ideally, each of the groups will be shot over a chrono, so you have the actual average velocity for that group.
Re: DC & ColdBore 1.0
Which manual? In FFS it's DK, in Coldbore it's DC. It's the deceleration constant, defaulting to .5 in both programs.
Which manual? In FFS it's DK, in Coldbore it's DC. It's the deceleration constant, defaulting to .5 in both programs.
Re: DC & ColdBore 1.0
Good folks, I was tempted to leave this one alone, but I just have to try to help since I know a bit about CB1. Far from knowing all there is to know about it, but I have done some of my homework.
I think it’s important to recognize that the <span style="font-weight: bold">DK in (FFS)</span> and <span style="font-weight: bold">DC in (CB1)</span> are not the same figure.
The ballistics engines of both program are quite different, and having been there with both, I can attest that the DK and DC are not exchangeable. As far as I can tell the differences, FFS is based off of the Pejsa method while CB1 runs on a proprietary algorithm.
A practical way to see them is that the BC models the drag curve shape and the DC adjusts it for final tuning.
The DC default value of 0.500 is plenty accurate, and given a proper BC it will return to the user very accurate fire solutions, capable of matching Doppler radar tracks.
The DC (or the BC by the same token), cannot be computed accurately based on "drop" values. In the User's Manual of ColdBore you can find an explanation, that I quote here literally.
<span style="color: #CC0000">WARNING: It's important to remark, that this program does not favor any other method to evaluate it, especially those based on measuring Drop at a certain range, because there are so many errors that can be introduced it doesn't lend itself as being very viable. Its determination is totally affected by shooter/gun errors and in fact does not represent the actual problem of velocity, which can be measured very precisely by means which are both available and affordable.</span>
Problem is that both the BC and the DC are quite sensitive to errors coming from inaccurate range measurements or downrange velocity figures or both...also remember that the DC (and the BC) are way sensitive to even small changes in velocity loss.
The POI method is too prone to cumulative and unaccounted for errors.
One very critical feature of the DC is its ability to tell “how good” the BC is. If the BC is of good “quality”y, then the DC defaults value (0.500 is a perfectly one. If you have to deviate it more than +/- 10% then the BC is quite doubtful and must be discarded.
Good folks, I was tempted to leave this one alone, but I just have to try to help since I know a bit about CB1. Far from knowing all there is to know about it, but I have done some of my homework.
I think it’s important to recognize that the <span style="font-weight: bold">DK in (FFS)</span> and <span style="font-weight: bold">DC in (CB1)</span> are not the same figure.
The ballistics engines of both program are quite different, and having been there with both, I can attest that the DK and DC are not exchangeable. As far as I can tell the differences, FFS is based off of the Pejsa method while CB1 runs on a proprietary algorithm.
A practical way to see them is that the BC models the drag curve shape and the DC adjusts it for final tuning.
The DC default value of 0.500 is plenty accurate, and given a proper BC it will return to the user very accurate fire solutions, capable of matching Doppler radar tracks.
The DC (or the BC by the same token), cannot be computed accurately based on "drop" values. In the User's Manual of ColdBore you can find an explanation, that I quote here literally.
<span style="color: #CC0000">WARNING: It's important to remark, that this program does not favor any other method to evaluate it, especially those based on measuring Drop at a certain range, because there are so many errors that can be introduced it doesn't lend itself as being very viable. Its determination is totally affected by shooter/gun errors and in fact does not represent the actual problem of velocity, which can be measured very precisely by means which are both available and affordable.</span>
Problem is that both the BC and the DC are quite sensitive to errors coming from inaccurate range measurements or downrange velocity figures or both...also remember that the DC (and the BC) are way sensitive to even small changes in velocity loss.
The POI method is too prone to cumulative and unaccounted for errors.
One very critical feature of the DC is its ability to tell “how good” the BC is. If the BC is of good “quality”y, then the DC defaults value (0.500 is a perfectly one. If you have to deviate it more than +/- 10% then the BC is quite doubtful and must be discarded.
Re: DC & ColdBore 1.0
Patagonia is based off the Pesja Model, it uses that as a foundation which is why both it and FFS are so similar and why they are much different from Point Mass solvers.
While Patagonia does use "some" propriety code, it is in fact a Pesja based solver as written by them,
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">he ballistics engine of the Desktop & Mobile editions© while based on the work of Professor Arthur J. Pejsa ( who finished his research circa 1953 ) includes numerous proprietary extensions, making it a highly developed derivation of Pejsa's original method. Meaning it has no velocity or range restrictions, covering the full spectrum from supersonic, transonic and subsonic trajectories at extended ranges with muzzle velocities starting at any sonic boundary, giving a continuous, non-linear solution.</div></div>
http://www.patagoniaballistics.com/balengine.html
Patagonia is based off the Pesja Model, it uses that as a foundation which is why both it and FFS are so similar and why they are much different from Point Mass solvers.
While Patagonia does use "some" propriety code, it is in fact a Pesja based solver as written by them,
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">he ballistics engine of the Desktop & Mobile editions© while based on the work of Professor Arthur J. Pejsa ( who finished his research circa 1953 ) includes numerous proprietary extensions, making it a highly developed derivation of Pejsa's original method. Meaning it has no velocity or range restrictions, covering the full spectrum from supersonic, transonic and subsonic trajectories at extended ranges with muzzle velocities starting at any sonic boundary, giving a continuous, non-linear solution.</div></div>
http://www.patagoniaballistics.com/balengine.html
Re: DC & ColdBore 1.0
Directly from the horse’s mouth (08/23/2010 on the LRH forum)
http://www.longrangehunting.com/forums/f...206/index2.html
<span style="color: #3333FF">“…LB3 does not use the Pejsa method.
It's a proprietary algorithm, with many extensions to Dr. Pejsa's method.
During the development phase, Dr. Pejsa was very kind to discuss the new algorithm math and that's why he is credited as having provided the original concept.
The current algorithm employed in LB3 took over two years to develop, and the only part that has some resemblances is in how to model the Drag curve.
Please check the following article that shows some differences in the predictions made by some methods.
Ballistics and Predictions
While the article does not discuss the inner aspects of the algorithms and the math behind them (clearly out of scope), the general idea is exposed when comparing their outcome…”</span>
At that time I was running Patagonia’s software for over 3 years (having transitioned for free from LB2), and was puzzled by the very same reference posted by Lowlight, so I decided to email them on this question, in order to gain more insight.
The answer was quite clear. Some points from it as follows
· The ballistics engine is NOT Pejsa.
· Dr. Pejsa is still credited for having provided the original framework.
· Having him recognized is a tribute to his original research.
· The differences are many and most of them are quite critical given their radical departure.
And what could be better than comparing CB1 to the original, I mean Dr. Pejsa’s own program?
I did precisely that (call me a ballistics software junkie) and the results were non-convergent as the transonic zone was approached. Same output when comparing CB1 to many other implementations of Pejsa’s original method.
Like I stated before, my understanding is that FFS runs Pejsa, and I can say for sure, that the DK (FFS) and the DC (CB1) are not the same.
From my email exchange with Patagonia I also learned some more significant things that helped me to understand, a little bit more, why FFS and CB1 are different animals, but that I save for another topic.
All in all, CB1 engine is a <span style="color: #3333FF">“highly developed derivation” (paraphrasing their own web statement), which must no be taken as being “Pejsa-based”.</span> <span style="color: #CC0000">In math, a “derivation” usually implies a new and original method and that’s <span style="font-weight: bold">the reason for being a “proprietary” one.</span></span>
http://www.longrangehunting.com/articles/ballistics-predictions-1.php
Directly from the horse’s mouth (08/23/2010 on the LRH forum)
http://www.longrangehunting.com/forums/f...206/index2.html
<span style="color: #3333FF">“…LB3 does not use the Pejsa method.
It's a proprietary algorithm, with many extensions to Dr. Pejsa's method.
During the development phase, Dr. Pejsa was very kind to discuss the new algorithm math and that's why he is credited as having provided the original concept.
The current algorithm employed in LB3 took over two years to develop, and the only part that has some resemblances is in how to model the Drag curve.
Please check the following article that shows some differences in the predictions made by some methods.
Ballistics and Predictions
While the article does not discuss the inner aspects of the algorithms and the math behind them (clearly out of scope), the general idea is exposed when comparing their outcome…”</span>
At that time I was running Patagonia’s software for over 3 years (having transitioned for free from LB2), and was puzzled by the very same reference posted by Lowlight, so I decided to email them on this question, in order to gain more insight.
The answer was quite clear. Some points from it as follows
· The ballistics engine is NOT Pejsa.
· Dr. Pejsa is still credited for having provided the original framework.
· Having him recognized is a tribute to his original research.
· The differences are many and most of them are quite critical given their radical departure.
And what could be better than comparing CB1 to the original, I mean Dr. Pejsa’s own program?
I did precisely that (call me a ballistics software junkie) and the results were non-convergent as the transonic zone was approached. Same output when comparing CB1 to many other implementations of Pejsa’s original method.
Like I stated before, my understanding is that FFS runs Pejsa, and I can say for sure, that the DK (FFS) and the DC (CB1) are not the same.
From my email exchange with Patagonia I also learned some more significant things that helped me to understand, a little bit more, why FFS and CB1 are different animals, but that I save for another topic.
All in all, CB1 engine is a <span style="color: #3333FF">“highly developed derivation” (paraphrasing their own web statement), which must no be taken as being “Pejsa-based”.</span> <span style="color: #CC0000">In math, a “derivation” usually implies a new and original method and that’s <span style="font-weight: bold">the reason for being a “proprietary” one.</span></span>
http://www.longrangehunting.com/articles/ballistics-predictions-1.php
Re: DC & ColdBore 1.0
How are two of the same numbers doing the same thing with the same values not the same ?
So you have run FFS and compared it side by side to CB1 or even LB3 ? You don't see how these two programs have the same number that work in the same place to tweak the curve are similar ?
Well that is interesting, seeing how I have run both side by side and I get similar results. Sure some minor differences but just because one is .2 mils off the other doesn't make them so different at least to most people.
But then again, I am not a cheerleader for either other to say they both beat Point Mass solvers
How are two of the same numbers doing the same thing with the same values not the same ?
So you have run FFS and compared it side by side to CB1 or even LB3 ? You don't see how these two programs have the same number that work in the same place to tweak the curve are similar ?
Well that is interesting, seeing how I have run both side by side and I get similar results. Sure some minor differences but just because one is .2 mils off the other doesn't make them so different at least to most people.
But then again, I am not a cheerleader for either other to say they both beat Point Mass solvers
Re: DC & ColdBore 1.0
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">How are two of the same numbers doing the same thing with the same values not the same ?
So you have run FFS and compared it side by side to CB1 or even LB3 ? You don't see how these two programs have the same number that work in the same place to tweak the curve are similar ?
Well that is interesting, seeing how I have run both side by side and I get similar results. Sure some minor differences but just because one is .2 mils off the other doesn't make them so different at least to most people.
But then again, I am not a cheerleader for either other to say they both beat Point Mass solvers
</div></div>
I never said that the DK (FFS) and DC (CB1) do not work the same in regards to adjusting the curve…I just said that they are not exchangeable.
And according to my own comparisons they are not within 0.2 MILS, which can be a lot or not, depending on range.
In the following runs it can be appreciated what I said before, as the transonic zone is being approached the results are diverging, which led me to realize that FFS is based off Pejsa “as is”, since the trend is essentially the same with respect to Dr. Pejsa’s own program.
Data 1
Baro = 29.90
Temp = 65 F
RH = 50%
MV = 2900
BC = 0.583 (G1)
DK (FFS) = 0.460
DC (CB1) = 0.460
SH = 2.0 in
ZR = 200 y
Wind Dir = 270
Wind Speed = 5 mph
Path (1000y)
FFS = -304.2 in / 29.05 MOA / 8.4 MRAD
CB1 = -276.1 in / 26.4 MOA / 7.7 MRAD
------------------------------------------------------------------------------------
Data 2
Baro = 29.53
Temp = 10 F
RH = 50%
MV = 2770
BC = 0.640 (G1)
DK (FFS) = 0.500
DC (CB1) = 0.500
SH = 1.5 in
ZR = 300 y
Wind Dir = 270
Wind Speed = 5 mph
Path (1000m)
FFS = -379.0 in / 33.1 MOA / 9.6 MRAD
CB1 = -353.8 in / 30.9 MOA / 9.0 MRAD
------------------------------------------------------------------------------------
Data 3
Baro = 29.53
Temp = 59 F
RH = 78%
MV = 2950
BC = 0.583 (G1)
DK (FFS) = 0.461
DC (CB1) = 0.461
SH = 2.0 in
ZR = 200 y
Wind Dir = 270
Wind Speed = 5 mph
Path (1000y)
FFS = -289.9 in / 27.7 MOA / 8.0 MRAD
CB1 = -264.8 in / 25.3 MOA / 7.4 MRAD
Lowlight, it has never been my intention to make any of my posts a personal attack to folks. I have always tried to be respectful and considerate. If I have ever offended you or any one else I'm apologizing for that.
My post above was not intended to be disrespectful but just merely provide information for your readers.
The post was not about what I understand or not, not about what I can see or not, I merely was stating what has previously been said by CB1.0's developer.
Frank, I've got lots to learn from you and I respect your knowledge and abilities. With that said, if in any way my presence is not welcome in your forum please let me know.
Respectfully,
Eaglet
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">How are two of the same numbers doing the same thing with the same values not the same ?
So you have run FFS and compared it side by side to CB1 or even LB3 ? You don't see how these two programs have the same number that work in the same place to tweak the curve are similar ?
Well that is interesting, seeing how I have run both side by side and I get similar results. Sure some minor differences but just because one is .2 mils off the other doesn't make them so different at least to most people.
But then again, I am not a cheerleader for either other to say they both beat Point Mass solvers
</div></div>
I never said that the DK (FFS) and DC (CB1) do not work the same in regards to adjusting the curve…I just said that they are not exchangeable.
And according to my own comparisons they are not within 0.2 MILS, which can be a lot or not, depending on range.
In the following runs it can be appreciated what I said before, as the transonic zone is being approached the results are diverging, which led me to realize that FFS is based off Pejsa “as is”, since the trend is essentially the same with respect to Dr. Pejsa’s own program.
Data 1
Baro = 29.90
Temp = 65 F
RH = 50%
MV = 2900
BC = 0.583 (G1)
DK (FFS) = 0.460
DC (CB1) = 0.460
SH = 2.0 in
ZR = 200 y
Wind Dir = 270
Wind Speed = 5 mph
Path (1000y)
FFS = -304.2 in / 29.05 MOA / 8.4 MRAD
CB1 = -276.1 in / 26.4 MOA / 7.7 MRAD
------------------------------------------------------------------------------------
Data 2
Baro = 29.53
Temp = 10 F
RH = 50%
MV = 2770
BC = 0.640 (G1)
DK (FFS) = 0.500
DC (CB1) = 0.500
SH = 1.5 in
ZR = 300 y
Wind Dir = 270
Wind Speed = 5 mph
Path (1000m)
FFS = -379.0 in / 33.1 MOA / 9.6 MRAD
CB1 = -353.8 in / 30.9 MOA / 9.0 MRAD
------------------------------------------------------------------------------------
Data 3
Baro = 29.53
Temp = 59 F
RH = 78%
MV = 2950
BC = 0.583 (G1)
DK (FFS) = 0.461
DC (CB1) = 0.461
SH = 2.0 in
ZR = 200 y
Wind Dir = 270
Wind Speed = 5 mph
Path (1000y)
FFS = -289.9 in / 27.7 MOA / 8.0 MRAD
CB1 = -264.8 in / 25.3 MOA / 7.4 MRAD
Lowlight, it has never been my intention to make any of my posts a personal attack to folks. I have always tried to be respectful and considerate. If I have ever offended you or any one else I'm apologizing for that.
My post above was not intended to be disrespectful but just merely provide information for your readers.
The post was not about what I understand or not, not about what I can see or not, I merely was stating what has previously been said by CB1.0's developer.
Frank, I've got lots to learn from you and I respect your knowledge and abilities. With that said, if in any way my presence is not welcome in your forum please let me know.
Respectfully,
Eaglet
Re: DC & ColdBore 1.0
Eaglet, LL, the DC/DK values are not exchangable, you can't us the same value in both programs. They do both work in the same fashion, but they are not interchangable between programs. A .461 value for DK in FFS is going to be flat out wrong, but in CB1 you could have a DSC value of .375 and have it be valid. A DK in FFS should be no less than .485 and no more than .515, if you are outside those numbers you are doing something wrong. I don't have enought DC values in CB1 to give a valid range estimate, but it's clearly MUCH wider than the DK values in FFS.
As to the azimuth value, in CB you'll need to include the declination to be precise, but in practice, you'll rarely be in a location where the declination differance would make more than a .1 mil change in a shot.
Eaglet, LL, the DC/DK values are not exchangable, you can't us the same value in both programs. They do both work in the same fashion, but they are not interchangable between programs. A .461 value for DK in FFS is going to be flat out wrong, but in CB1 you could have a DSC value of .375 and have it be valid. A DK in FFS should be no less than .485 and no more than .515, if you are outside those numbers you are doing something wrong. I don't have enought DC values in CB1 to give a valid range estimate, but it's clearly MUCH wider than the DK values in FFS.
As to the azimuth value, in CB you'll need to include the declination to be precise, but in practice, you'll rarely be in a location where the declination differance would make more than a .1 mil change in a shot.
Re: DC & ColdBore 1.0
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cstmwrks</div><div class="ubbcode-body">Eaglet, Lowlight,
I was hoping to ask a few "new user" questions about CB1 .
So far I've been finding most answers on my own but one is still bugging me a bit. For Coroilis to be enabled a known AZIMUTH must be entered. Anyhow the question is this: Azimuth = compass reading MINUS magnetic declination? Or just the compass reading direct?
Thanks,
Bill </div></div>
Bill, I could just answer your question, but just in case I'll say a bit more.
For Coriolis adjustments to be successful we need two peaces of information.
A)Latitude = "Where are you standing on earth" Latitudinal wise.
for example Carson City, Nevada I would use 39 (North); just off of
your GPS, smart phone or whatever.
B) Azimuth = The direccion you're shooting. In reference to true north. My GPS runs using TN I aim it at the target and that angle I enter as Azimuth.... It goes True North =0 rotating to the right all the way to 360°. If you use a compas you would need to know the magnetic declination to compensate and obtain your true North reading off of.
If you have issues with setting it up properly for spin drift let me know.
Good Day.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cstmwrks</div><div class="ubbcode-body">Eaglet, Lowlight,
I was hoping to ask a few "new user" questions about CB1 .
So far I've been finding most answers on my own but one is still bugging me a bit. For Coroilis to be enabled a known AZIMUTH must be entered. Anyhow the question is this: Azimuth = compass reading MINUS magnetic declination? Or just the compass reading direct?
Thanks,
Bill </div></div>
Bill, I could just answer your question, but just in case I'll say a bit more.
For Coriolis adjustments to be successful we need two peaces of information.
A)Latitude = "Where are you standing on earth" Latitudinal wise.
your GPS, smart phone or whatever.
B) Azimuth = The direccion you're shooting. In reference to true north. My GPS runs using TN I aim it at the target and that angle I enter as Azimuth.... It goes True North =0 rotating to the right all the way to 360°. If you use a compas you would need to know the magnetic declination to compensate and obtain your true North reading off of.
If you have issues with setting it up properly for spin drift let me know.
Good Day.
Re: DC & ColdBore 1.0
I can tell you a way to cheat and get a really close DC in LB3 or at least it works for my rifle. Chrono you round at 10' or whatever you prefer and enter that into the program along with current conditions. After entering the data, go to the results screen and write down the calculated velocities for 0,100,200,300 yards and use those numbers to calculate the DC. The reason I say this works for mine is because I shot a 5 shot string at each distance to get average speeds for each input and they were +/- 20fps of the calculated FPS from just entering the 10' data. Not sure how much difference the correct DC makes shooting steel but it couldnt hurt knowing.
I can tell you a way to cheat and get a really close DC in LB3 or at least it works for my rifle. Chrono you round at 10' or whatever you prefer and enter that into the program along with current conditions. After entering the data, go to the results screen and write down the calculated velocities for 0,100,200,300 yards and use those numbers to calculate the DC. The reason I say this works for mine is because I shot a 5 shot string at each distance to get average speeds for each input and they were +/- 20fps of the calculated FPS from just entering the 10' data. Not sure how much difference the correct DC makes shooting steel but it couldnt hurt knowing.
Re: DC & ColdBore 1.0
If that's your solution, just leave it at the default of .5, you'll be better off.
If that's your solution, just leave it at the default of .5, you'll be better off.
Re: DC & ColdBore 1.0
That was my point,
That both default at .5 and both do the same thing, not that you can interchange the numbers and they will work the same. Most of the time, there is no need to change them off .5, however if you do need to change it, in either program you get essentially the same results, "an adjustment of the curve" as required to tweak your data. Not that they interchange, just that the programs are much more similar to each then it being given credit too.
That was my point,
That both default at .5 and both do the same thing, not that you can interchange the numbers and they will work the same. Most of the time, there is no need to change them off .5, however if you do need to change it, in either program you get essentially the same results, "an adjustment of the curve" as required to tweak your data. Not that they interchange, just that the programs are much more similar to each then it being given credit too.
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