The ColdBore Comparison

[Lowlight]

Lots of discussion on what software is better, how they handle the differences between G1 & G7 models, and finally how it all compares to Doppler Radar.

Having shot over Doppler and seeing how it operates, how far they can track a bullet, I thought this might help.

ColdBore (previously Loadbase) has been around a very long time. Like Field Firing Solutions, these guys were early on the scene with a non-Point Mass approach. Now it's Point Mass to a certain degree, but it does deviate significantly in how they handle the predictions.







Part of the early discussions revolved around ColdBore being very complex. More than 9x the amount of code is involved in getting a ColdBore Prediction vs the competition.

Feel free to discuss,

 

[damoncali]

What's interesting to me is that the differences in results appear to be largely due to poor data on subsonic drag. At the speed of sound, the trajectories diverge dramatically. It's tough to tell without more information, but it looks to me like the curves would match up pretty well if perhaps we spent more time looking at drag at low velocities and tweaked the models, given how much time the bullets spend at low velocity in ELR.

We spend a lot of time looking at supersonic drag curves, a little more time at transonic, but then tend to just ignore subsonic. If you look at a real bullet's drag function, you tend to find very good agreement with both G1 and G7 in the low to moderate supersonic region (which is why both work perfectly well for most shooters out to 1000 yards or so). Both fall apart pretty badly in the transonic region just above Mach 1.0, and G1 tends to be terrible at very high mach numbers. What tends to get neglected is that the subsonic drag predicted by G1 and G7 can be pretty far off of reality. Usually, that doesn't matter because sane people try to stay supersonic.

Unfortunately, supersonic and subsonic aerodynamics are dramatically different. It makes me wonder what an optimal bullet would look like if you knew ahead of time that it would spend most of its fight at subsonic speed. At 3000m or whatever, subsonic performance can't be an afterthought.

 

[_Windrider_]

What's interesting to me is that the differences in results appear to be largely due to poor data on subsonic drag. At the speed of sound, the trajectories diverge dramatically. It's tough to tell without more information, but it looks to me like the curves would match up pretty well if perhaps we spent more time looking at drag at low velocities and tweaked the models, given how much time the bullets spend at low velocity in ELR.

We spend a lot of time looking at supersonic drag curves, a little more time at transonic, but then tend to just ignore subsonic. If you look at a real bullet's drag function, you tend to find very good agreement with both G1 and G7 in the low to moderate supersonic region (which is why both work perfectly well for most shooters out to 1000 yards or so). Both fall apart pretty badly in the transonic region just above Mach 1.0, and G1 tends to be terrible at very high mach numbers. What tends to get neglected is that the subsonic drag predicted by G1 and G7 can be pretty far off of reality. Usually, that doesn't matter because sane people try to stay supersonic.

Unfortunately, supersonic and subsonic aerodynamics are dramatically different. It makes me wonder what an optimal bullet would look like if you knew ahead of time that it would spend most of its fight at subsonic speed. At 3000m or whatever, subsonic performance can't be an afterthought.

Ever look at a golf ball and wonder how it can fly as far and as fast as it does?

When I was in college we tested 2 wing prototypes in the wind tunnel to help bring the laminar flow of the air further back on the chord in order to reduce drag and aid in lift. One version had a bunch of pinholes (I’m simplifying) with suction in each hole literally pulling the air to the skin of the wing. The other was a dimples wing much like a golf ball. Both were promising. I can’t help but wonder if a dimpled projectile could have some benefit, after all a bullet is just a different type of airfoil than a wing.

 

[Long Range 338]

Other apps can work too, but seem best using two profiles, one for short and on for ELR.




Sent from my iPhone using Tapatalk Pro

At what distance or speed do you recommend using for the ELR profile?

 

[Bigwheels]

Would have been really good to have had FFS included with the data.
Curious about the AB data. Was that using the custom drag curves or just the published BC?

 

[THEIS]

Ever look at a golf ball and wonder how it can fly as far and as fast as it does?

Hi,

In 2009 the Aberdeen the "Long Range Projectile Project" tested dimpled projectiles.
In 2011 the Italian company "CompBullet" designed and manufactured projectiles with "ports" machined radially around the projectile.

Sincerely,
THEIS

 

[_Windrider_]

Hi,

In 2009 the Aberdeen the "Long Range Projectile Project" tested dimpled projectiles.
In 2011 the Italian company "CompBullet" designed and manufactured projectiles with "ports" machined radially around the projectile.

Sincerely,
THEIS

Good info. It was 1999 when I did it. But you may want to read this:

http://bulletin.accurateshooter.com/...l-web-readers/

i have ave no doubt the other one is a hoax as well. I was actually being serious about the dimples. Just pondering out loud but a ported projectile the way I described is impossible since it requires vacuum pressure. Simply drilling holes will do nothing. Anyway. Carry on.

 

[THEIS]

Good info. It was 1999 when I did it. But you may want to read this:

http://bulletin.accurateshooter.com/...l-web-readers/

i have ave no doubt the other one is a hoax as well.

Hi,

Yes they were hoax lol. The dimpled bullet talk always comes up somewhere or another when discussion of transonic to subsonic gets going.
But on serious note....wasnt there some guy in Australia playing with some crazy projectile design years ago that was claiming superior transonic stability?


Sincerely,
THEIS

 

[_Windrider_]

Hi,

Yes they were hoax lol. The dimpled bullet talk always comes up somewhere or another when discussion of transonic to subsonic gets going.
But on serious note....wasnt there some guy in Australia playing with some crazy projectile design years ago that was claiming superior transonic stability?


Sincerely,
THEIS

I’m not sure how it would affect transonic stability, but it could reduce drag and there fore allow a projectile to stay supersonic longer. I think the only think that could help stability in transonic to subsonic would be a finned projectile which I know there have been some tests/discussion on that in the past but probably not practical for small arms.

 

[Bulletsmith]

Many years ago when the Moly coating was getting started(95?) A fella told me that the reason you had to put ball bearings in the tumbler was that it dimpled the bullet and made the bullet fly better. I mentioned it was for impacting the moly on the bullet, he disagreed.

 

[LastShot300]

Lots of discussion on what software is better, how they handle the differences between G1 & G7 models, and finally how it all compares to Doppler Radar.

Having shot over Doppler and seeing how it operates, how far they can track a bullet, I thought this might help.

ColdBore (previously Loadbase) has been around a very long time. Like Field Firing Solutions, these guys were early on the scene with a non-Point Mass approach. Now it's Point Mass to a certain degree, but it does deviate significantly in how they handle the predictions.

Part of the early discussions revolved around ColdBore being very complex. More than 9x the amount of code is involved in getting a ColdBore Prediction vs the competition.

Feel free to discuss,

Thanks for sharing, clearly an image is worth a thousand words. I've never reached 3000 but 2300-2700 and the images supports both my views and experience of CB vs. the other programs mainly the different flavors of the Point Mass (even when running drag curves) that are legion nowadays. As said many times before, of all the stuff that's available only CB and FFS are worth the money for true LR work.

 

[Ewen]

Diver160651 has managed to write almost word for word my experience as well. In general most apps will get you there within 750m however once you go past that then the failures in the algorithm really start to show through.
Truing is NOT the answer, this only alters the curve shape a little and corrects for the trued range, if the curve is fundamentally wrong then no amount of truing can create for you a solution that is correct at all ranges. I have also used and taught the concept of two or more curves per round however this is a workaround and a weak one at that, it would be much easier (and more correct) if the user for using Coldbore in the first place.
Ewen

 

[Lowlight]

Glad we are having this discussion, and hopefully, we can push this variation forward.

One observation when playing with the Revic Scope and the App associated with it. When I set up the track I added the data directly and did not "true it", once that was done I shot the rifle 100% by the use of the scope and software. One of the nice things about my range, beyond having targets every 100 yards to a mile, was the fact I have smallish targets to include a 1 MOA Plate rack at 500 yards.



Also, many of my plates have watermarks across the center for gauging offset (POA vs POI), gives me a better idea of where my impacts are. The Gunwerks, Revic software was spot on until 1400 yards, then it deviated by 10 yards, and at 1500 it was off by 25 yards.

It highlights the fact that once you cross a certain point the variations increase. You can now visualize the angle spreading. It opens the door for two tracks as noted above, one short to medium range and one long to ELR Range. However, it seems wide open for another "Fix" to correct the fact that most of this software does not know where the bullet was 100 yards before and will it will be 100 yards after. ColdBore does this, it knows where the bullet was and where it will be which is why CB has the ability to give you better ELR predictions.

There have been times in classes guys have one or the other not match up and we create two profiles. This is a cheap fix but it should not be our solution. The guys doing this should work to address these very real limitations to distance.

 

[_Windrider_]

Glad we are having this discussion, and hopefully, we can push this variation forward.

One observation when playing with the Revic Scope and the App associated with it. When I set up the track I added the data directly and did not "true it", once that was done I shot the rifle 100% by the use of the scope and software. One of the nice things about my range, beyond having targets every 100 yards to a mile, was the fact I have smallish targets to include a 1 MOA Plate rack at 500 yards.



Also, many of my plates have watermarks across the center for gauging offset (POA vs POI), gives me a better idea of where my impacts are. The Gunwerks, Revic software was spot on until 1400 yards, then it deviated by 10 yards, and at 1500 it was off by 25 yards.

It highlights the fact that once you cross a certain point the variations increase. You can now visualize the angle spreading. It opens the door for two tracks as noted above, one short to medium range and one long to ELR Range. However, it seems wide open for another "Fix" to correct the fact that most of this software does not know where the bullet was 100 yards before and will it will be 100 yards after. ColdBore does this, it knows where the bullet was and where it will be which is why CB has the ability to give you better ELR predictions.

There have been times in classes guys have one or the other not match up and we create two profiles. This is a cheap fix but it should not be our solution. The guys doing this should work to address these very real limitations to distance.

Frank, what caliber you using to test the Revic?

one thought I’ve had in reading this and some other threads is, and this is something I have no idea because I’m not all that familiar with the various programs algorithms or calculation methodology, but do they assume that transonic to supersonic is always at the same speed? Do any of the calculators account for the fact that it changes with temperature? Could this be one of the reasons some require truing and some do not? If I’m shooting at 68f where speed of sound is 1125 FPS, if I then shoot at 32f, does my Calculator take into account that the speed of sound is actually 1087 FPS. Do the calculators compensate for this or do they just use a fixed number?

 

[Lowlight]

They all say they calculate for the changes in air density like with elevation, etc, sometimes I am not so sure they are doing it right.

260REM for the Revic

 

[_Windrider_]

They all say they calculate for the changes in air density like with elevation, etc, sometimes I am not so sure they are doing it right.

260REM for the Revic

Well if they are using density I’d agree. Temperature is what affects it but I guess one could surmise that an increase in DA would change it because of the changes in temp but that only works when it’s standard pressure and temp for a given altitude.

 

[_Windrider_]

FWIW, ballistic AE seems to recognize the change but I can’t tell on AB because it doesn’t mark it on the drop sheet like Ballistic AE does so I have no idea. This at least makes me believe that it is properly being accounted for in some programs. But I could be wrong, they could just simply be making it easily seen so the shooter knows. As with anything, it requires range time. No complaints about that.

 

[Lowlight]

FWIW, ballistic AE seems to recognize the change but I can’t tell on AB because it doesn’t mark it on the drop sheet like Ballistic AE does so I have no idea. This at least makes me believe that it is properly being accounted for in some programs. But I could be wrong, they could just simply be making it easily seen so the shooter knows. As with anything, it requires range time. No complaints about that.

Sometimes it appears it just shows the sound barrier crossing to the next closest velocity that crosses the line. So it's hard to tell as it's just throws a highlight line between the numbers.

Diver,
Ya, they spent a week at Raton to true up their software, I think only one other team did that, maybe even no other team rented Whittington like Team AB did. They are doing good work ELR wise but just saying, "use what we use" is not the whole story.

 

[The King]

I do wish coldbore would get with it and release an ipad app.

 

[LastShot300]

Glad we are having this discussion, and hopefully, we can push this variation forward.

It highlights the fact that once you cross a certain point the variations increase. You can now visualize the angle spreading. It opens the door for two tracks as noted above, one short to medium range and one long to ELR Range. However, it seems wide open for another "Fix" to correct the fact that most of this software does not know where the bullet was 100 yards before and will it will be 100 yards after. ColdBore does this, it knows where the bullet was and where it will be which is why CB has the ability to give you better ELR predictions.

There have been times in classes guys have one or the other not match up and we create two profiles. This is a cheap fix but it should not be our solution. The guys doing this should work to address these very real limitations to distance.

If memory serves me well, the way CB does it deed was, somewhat, explained on this very forum some years ago. Frank nailed it again.

Frank,

Exactly the reason I brought up the two curve solution; to illustrate how poorly some of these programs are and what drastic curve fitting does.

Doc just posted something to the effect how we need AB to shoot ELR as it is the winningest.. you know as well as I do, these guys re-fit curves on site or just gathered dope and no way does the AB curve that works at 2500m, work dead on at 700..

Enough said.

Diver160651 has managed to write almost word for word my experience as well. In general most apps will get you there within 750m however once you go past that then the failures in the algorithm really start to show through.
Truing is NOT the answer, this only alters the curve shape a little and corrects for the trued range, if the curve is fundamentally wrong then no amount of truing can create for you a solution that is correct at all ranges. I have also used and taught the concept of two or more curves per round however this is a workaround and a weak one at that, it would be much easier (and more correct) if the user for using Coldbore in the first place.
Ewen

Crystal. All "trajectory validation" mechanisms are essentially worthless unless your work is always done inside a definite bracket. One of the reasons CB does not feature it, is simply because there are better ways to do this. There is an online article where this mechanism is explained as well as highly praised by the author.

 

[Lowlight]

TRASOL was supposed to be the answer to CB being ported for iOS and Android, but they have not replaced their developer. Early on the model was to have a complete system, very similar to what AB is doing. In all the early conversations there was always a path to more and more systems working with TRASOL. I cannot say what stopped or slowed them down beyond knowing there is no developer right now working with them.

it would come down to funding to get ColdBore ported for both mobile systems. If you know a 3rd party with funding the engine could be used.

 

[damoncali]

Even maintaining a simple iOS/Android app costs a fortune to develop and support, let alone what it costs to integrate other systems. I can't for the life of me understand why anyone would want to sell consumer ballistics software without having some other angle (like selling bullets, rifles, etc). I considered it once, and even wrote a preliminary iOS app, and then when I realized how big a headache it would be, I just chucked the idea. There just isn't enough money in it to pay the rent.

It's also hugely difficult to find developers who get it. Most of them are used to building your typical app store bs or corporate apps. The blend of engineering knowledge, modern software development skill, and desire to work on this stuff is pretty rare. Most developers are going to need a lot of hand holding to make it work because they don't know squat about ballistics. Most engineers can't write software very well. It's tough.

 

[The King]

I was really hoping trasol would work out too.

 

[_Windrider_]

I was really hoping trasol would work out too.

The worse part of TRASOL is the total radio silence from DTA. At a minimum they should be refunding people their money and they certainly shouldn’t still be charging people in the App Store or even allowing it to be downloaded.

 

[Lowlight]

It works, I use it all the time. I had to re-install it, but once you do it goes right back to working correctly.

 

[CavReconScout]

I too was having issues with TRASOL but after reinstalling it no problems. I was even able to download my saved profiles.

 

[timintx]

This may be an anomaly but with my program on a particular bullet using G1 single bc, my come ups match inside of 2/10 moa once tweeked over time to 1760 yds,and then moved out to longer ranges in the 2500 yd 2600 yd area and still matched up to the click so far. I need more shots fired for the longer distances though and am not ready to make a decision on the 3000 to 4000 area to say for sure.but I am amazed that on this particular set up a single bc seems to work well into subsonic.I know physically it should not but it seems to be so far. I used sierras with multiple BC derived from dod style doppler and they matched up within 1 moa right out of the gate which left very little tweeking needed to get it dead on out to 3000yds at 1100 feet ASL which put the initial transonic barrier around 2000 yds and it still held to the calculated trajectories. It seems one minute this bullet does this best with 1 BC and the next bullet does best with multiple BC but the G1 seems to match thorough out the trajectory most accurately to me. The G7 matches up perfectly to 1200 yds but then starts to deviate and at 2400 yds or so the calculations start to come back to the actual dopes and is difficult to make match up perfectly to the inch through out the whole trajectory with multiple or single BC.

 

[timintx]

Hello Diver ,I am using Ballisitc AE which uses a JBM engine .

 

[Lowlight]

I like Ballistic AE a lot, great library, solid interface, I don't think there is an Android version which is the only downside to recommending it. (unless they added one and I missed it)

The fact your G1 profiles works is two fold, one JBM does not punish you for using G1 like other 3DOF programs do, and two, you got lucky, it is what it is. That is a good thing.

This comes back to the fact, or I should say the discussion earlier, that if all these programs are using basically the same Point Mass calculations, why do they not all act the same. Well because guys want to inject their own bias into the equation and force you to follow their lead. ( ex. You must use G7, to promote that argument they intentionally bias the G1 performance)

 

[The King]

THIS was one of the better things I had read on this forum lol. Reinstalled and it worked great.

I would love to see TRASOL float back up to the top. It was really innovative. A few more features and I think it could win the whole shebang.

a) I wish I could turn the HUD reticle off or into a dot or something. That way I could use the reticle in my spotter in that space a little easier. ALSO, I would love to have a calibratable mildot reticle that you could use to make a non-reticle spotter have a reticle in the phone.
b) bullet library would be nice.
c) integration with weather meters and lasers
d) fix the range bubble to always be visible when you are sliding it.

Does this use the ColdBore solver in it?

It works, I use it all the time. I had to re-install it, but once you do it goes right back to working correctly.

 

[LastShot300]

This may be an anomaly but with my program on a particular bullet using G1 single bc, my come ups match inside of 2/10 moa once tweeked over time to 1760 yds,and then moved out to longer ranges in the 2500 yd 2600 yd area and still matched up to the click so far. I need more shots fired for the longer distances though and am not ready to make a decision on the 3000 to 4000 area to say for sure.but I am amazed that on this particular set up a single bc seems to work well into subsonic.I know physically it should not but it seems to be so far. I used sierras with multiple BC derived from dod style doppler and they matched up within 1 moa right out of the gate which left very little tweeking needed to get it dead on out to 3000yds at 1100 feet ASL which put the initial transonic barrier around 2000 yds and it still held to the calculated trajectories. It seems one minute this bullet does this best with 1 BC and the next bullet does best with multiple BC but the G1 seems to match thorough out the trajectory most accurately to me. The G7 matches up perfectly to 1200 yds but then starts to deviate and at 2400 yds or so the calculations start to come back to the actual dopes and is difficult to make match up perfectly to the inch through out the whole trajectory with multiple or single BC.

Frank said it, you got lucky and don't overlook the fact that you have to tweak the data and use multiple BCs, which is what Diver160151 detailed before, basically what you did is to create two "different profiles". Indeed the use of multiple BCs is akin to the idea of a "custom drag", basically the same thing, since one comes out the other.

The overall point here that really matters is software like CB or FFS are much more accurate right out of the box and will do that with either a single G1 or G7 number, provided those are well defined and behaved.

 

[timintx]

I like Ballistic AE a lot, great library, solid interface, I don't think there is an Android version which is the only downside to recommending it. (unless they added one and I missed it)

The fact your G1 profiles works is two fold, one JBM does not punish you for using G1 like other 3DOF programs do, and two, you got lucky, it is what it is. That is a good thing.

This comes back to the fact, or I should say the discussion earlier, that if all these programs are using basically the same Point Mass calculations, why do they not all act the same. Well because guys want to inject their own bias into the equation and force you to follow their lead. ( ex. You must use G7, to promote that argument they intentionally bias the G1 performance)

That makes perfect sense to me Frank and seems to explain some of the differences between the different programs I have read about. I still have a lot to learn about the different programs but each thread is helping me to understand better so please forgive my ignorance on these matters. Unfortunately Ballistic said they were not planning to go to any other version for apps at the time I inquired . I will start testing again soon in the 3000yd + area and then reconfirming my come ups .if it is luck I am good with that too,god knows I have had my share of bad luck. lol

 

[timintx]

Frank said it, you got lucky and don't overlook the fact that you have to tweak the data and use multiple BCs, which is what Diver160151 detailed before, basically what you did is to create two "different profiles". Indeed the use of multiple BCs is akin to the idea of a "custom drag", basically the same thing, since one comes out the other.

The overall point here that really matters is software like CB or FFS are much more accurate right out of the box and will do that with either a single G1 or G7 number, provided those are well defined and behaved.

I agree last shot and will keep it in mind when I continue testing this spring.Thanks for the tip.

 

[Sil17sd]

How is 4dof working when put beside COLDBORE? I have had lots of success with 4dof. It seems to really do a better job than anything else I have on my phone. We went to 1350yds and I was only using my kestrel and had to spot and adjust for 5-6 rounds til we finally got consistent hits on a 16x16 in the windy conditions(14-16mph). Then got back to my phone entered the conditions into 4dof and it told me to dial exactly to where I ended up. ........ if I wouldve used it starting off we would've been on the steel right out of the gate.

 

[Lowlight]

I have to compare them,

This past weekend I shot the Pawnee Local Match and ran ColdBore alongside my Kestrel, after taking a different tack truing the software. I just automatically adjusted the BC first and then barely adjust the MV to the tune of 35fps and trued it up. ColdBore was straight, no adjustment and I got them to both to match up better.

Next one I will use the 4DOF but I have been having good luck with it, and have taken it past 1 Mile with good success.

 

[damoncali]

"G7 Is better than G1" has been blown way out of proportion and context, especially in the moderate super sonic range. The divergences are in transonic and below (where they both fall apart), and above what we consider normal velocities, where it isn't that important to us. In the range of Mach 1.5 - Mach 2.5, they are both very good approximations for most bullets. This chart illustrates it pretty well - it shows G1, G7 and Doppler drag functions for a Lapua Scenar 175gr .308. In the supersonic range, under a sane muzzle velocity, there just isn't much to worry about. That covers a whole lot of shooting scenarios for a whole lot of people. Yes, the better overall fit is G7 (for this bullet), but it's not the major problem people have come to believe.

 

[Lowlight]

I have been saying that for a very long time but everyone wants to argue that you HAVE to use G7

yes with some software it's better because they purposely make it work better, but with most shooting, it's irrelevant which you use

The part that escapes people is, these numbers are very velocity dependent, G1 more so, but both are velocity dependent

 

[damoncali]

Just human nature I guess. "G7 is likely a little better, the further you depart from short flat based hunting bullets" somehow becomes "OMGOUCANTHITANYTHINGWITHG1!!!" when you add Internet. Where I do have a gripe with G1's are with Sierra. They have some bullets that they report with banded G1's that vary so much that you can't really compare them to other manufacturers, which is to me the primary benefit of BC's. Exact DOPE I can get by shooting - I want to know which bullets to even try, and consistently measured BC's are a great comparison tool for consumers. When they're the only one reporting wildly varying G1's when a G7 would be fairly constant, that's just being difficult for no reason. Their 90 grain .224 Matchking, for example - it's impossible for a consumer to easily compare it to Berger's 90 VLD based on the info that Sierra provides - you have to run them through a ballistics calculator (and one that handles banded BC's, at that) to find out which is better. They makes some very good bullets, not sure why they're sticking to old methods when competitors like Hornady and Berger are stepping it up big time.