Berger Bullets Announces Launch of a New Ammo Company

[Michael Courtney]

I don't know what other independent tests you are referring to, but I will say that the majority of shooters on this forum, including some very experienced long range shooters, tend to agree that Berger's BC's are spot on. At least that has been my experience. Just throwing it out there...

Most experts in external ballistics discount inferring BCs based on drop data in favor of the two accepted reliable methods of using a near and far velocity measurement and using a near velocity measurement and an accurate time of flight over a known distance. When these methods are used, together with measured environmental conditions and entering the data into a reliable BC calculator, an accurate BC can be determined.

We use the near and far velocity method with chronographs calibrated to be accurate within 0.1%, chronograph separation measured with a tape measure accurate to within 3 inches, environmental conditions determined with a Kestrel 4500, and the JBM ballistics calculator. We also determine the BC for each of a number of shots which allows us not only to report the BC for a given near velocity but also to report the uncertainty in the BC. Our results correspond very closely with the published specifications of the Hornady AMAX and VMAX bullets that we have tested, but we tend to find bigger differences from published claims when testing other bullets.

If you can, please cite reliable results from using one of these two accepted methods, and we'll be happy to review the data for the specific bullets for which independent testing is available.

 

[SidecarFlip]

Myself, I consider Brian one of the most knowledgable in the field of applyied ballistics.

I'm sure the offerings of pre loaded cartridges were tested throughly.

It is difficult to find Berger projectiles, always has been. Nothing new there.

 

[cohunter14]

Most experts in external ballistics discount inferring BCs based on drop data in favor of the two accepted reliable methods of using a near and far velocity measurement and using a near velocity measurement and an accurate time of flight over a known distance.

Michael, you are far more intelligent than me when it comes to the science of this, but isn't the goal of a BC to determine the drop of a bullet? If you have one BC that represents the correct bullet drop and another that is scientifically correct, but doesn't work to produce the correct bullet drop, which one will you choose? The goal, in the end, is to hit your target at whatever range that is. So I don't care how the BC is decided upon or if someone tells me it is correct or not, what matters is that am I going to hit where I am aiming at any distance I choose. That, to me, is an 'acceptable method.'

 

[Michael Courtney]

Some other facts and clarifications:

Michael Courtney wrote:

It turns out all the data Bob McCoy used to establish the independence of drag coefficients on air density was taken at Aberdeen Proving Ground, near sea level. No one had ever empirically tested whether drag coefficients or BCs measured at sea level would give accurate predictions at higher elevations.

Bryan replied:

Are you kidding me? This is like doing a study to determine if the earth is round or flat. Altitude effects are well known and understood properties of the atmosphere. Aberdeen Proving Grounds may be located near sea level, but I think the 100's of artillery shots that were fired there and tracked with Doppler radar and telemetry to altitudes of many 1000's of feet altitude did a good job of exploring high altitude effects. If you manage to get a paper funded to study altitude effects of small arms at different altitude based on the premise that: "No-one's ever done it", it will be outright fraud.

The Air Force funded the study based on a proposal that pointed out that Bob McCoy's work was limited to sea level data. Certainly he had access to the artillery data you suggest, but in his paper, he is very clear he only used the spark range data:

"A large amount of high quality free flight total drag data is available at BRL from the firings of various models through the spark photography ranges."

This statement was made in his McDrag paper, and is an important part of the empirical justification for having drag coefficients in the 6 d.o.f. models depend only on velocity (or Mach number) and not on air density or Reynolds number. There are a number of other DoD publications that show that supersonic drag coefficients do generally depends on air density (through their dependence on Reynolds number).

Our paper on the independence of drag on air density for small arms projectiles has been through the approvals for public release and peer review process and will appear soon in print. It includes both the experimental results as well as a theoretical analysis of why the air density (thus Reynolds number) effects are small enough to neglect and still yield drag coefficients accurate to 1-2% over the range of air densities encountered in small arms fire. The peer reviewers did not raise any objections to the justifications for the study, the results, or the theoretical analysis. If you can cite papers showing prior work empirically justifying the independence of drag coefficients on air density for small arms projectiles, we would appreciate knowing of them.

As an aside, is anyone else curious to know why the Air Force is paying Michael Courtney to study Varmint bullets?

The DoD had a keen interest in developing generally accurate methods and models in ballistics. For models and methods to be general, they need to be tested using a range of projectiles. As it happens, military projectiles have much greater manufacturing variations than most sporting projectiles. We picked the 62 grain Berger Flatbase Varmint bullet because it was the same weight as the M855 and M855A1 projectiles, but offered tighter manufacturing tolerances and greater accuracy. We've tested a number of other varmint bullets of different weights in order to test our methods and models over a range of bullet weights and styles, using bullets of greater uniformity and accuracy than the M855. We further face the challenge that even though the DoD wants and expects their scientists to publish in the peer-reviewed literature, present at conferences, and otherwise be well engaged in the scientific community, DoD guidelines make it much harder to get test results approved for public release that include test results from currently fielded equipment.

What I do know is that Michaels wife Amy, and someone else named Joshua Courtney have co-authored several of these papers, so maybe it's a case of knowing the right people to get your hobby funded with government money. But this is pure speculation on my part.

Please cite the ballistics paper on which Joshua Courtney is a co-author, as it would be news to me. Not only is your speculation wrong, your facts are wrong also. The support the Air Force provided for our ballistics work included my salary, the purchase of some equipment, approval of my travel, peer-review of research proposals and scholarly papers, and approval of participation by collaborating Air Force scientists.

Neither our small company nor any family members ever received a penny of funding from the Air Force. (They have received funding from the Army and the Navy, but this funding resulted from processes I had little or no role in and certainly would withstand the strictest scrutiny regarding nepotism and undue influence. None of this work directly involved varmint bullets.)

 

[Michael Courtney]

Michael, you are far more intelligent than me when it comes to the science of this, but isn't the goal of a BC to determine the drop of a bullet?

Predicting drop is one goal of having accurate BCs. Depending on the application, accurate BCs are also important for accurately predicting wind drift and retained energy/retained velocity.

I first became interested in independently testing BC, not because of errant drop predictions but because of inadequate terminal performance. I had loaded a 115 grain VLD in my 25-06 Sendero, measured the muzzle velocity, and determined the drops out to 550 yards (the longest shot available at the farm I hunted). The predicted drops were slightly off when I shot the load at different ranges, but it was a simple matter to determine the proper scope adjustments. It was also difficult to be sure whether the difference in drops were due to imperfect scope adjustments, approximations in the scope height above the bore, or other factors that make bullet drop a poor choice for computing BCs.

When the day came for the 550 yard shot on a deer, there was no wind, I dialed in the elevation, and I put the 115 grain VLD right through both lungs of the deer, a perfect center punch. But when I drove over to where the deer stood, I couldn't find the deer and there was no blood trail. I looked around for a while and then gave up. The deer was found a few days later on a neighboring property. Inspecting the wounds showed that the bullet had penciled through the lungs without expanding.

We later measured the BC from this box of bullets to be 0.419 rather than the advertised 0.523. This gives a much smaller retained velocity at 550 yards, and even though the drop and shot were perfect, the bullet failed to expand resulting in a lost deer. The problem with the bullet was twofold: at the time Berger was using predicted rather than measured BCs. Later, Berger revised the BC of that bullet to be 0.466. Berger also determined that the bullets we were using had been made on an old die and were out of spec dimensionally. They sent us two new boxes of bullets, and we confirmed that the new boxes met their new BC spec.

Curiously, these are the only Berger Bullets we've tested that met their BC spec. All the Berger Bullets we've purchased from vendors have been a bit low, which is why I suspect they may have manufacturing issues leading to dimensional and BC variations over time.

We've done a lot of work in terminal performance, and impact velocity is a very important aspect of having accurate BCs.

 

[MMERSS]

FWIW, I conducted drop validation on two Berger bullets three weeks ago, the 230 Hybrid and 300 Hybrid. MV was in the 3100's and 3300's respectively. Twit was 1-10 for both rifles with a DA equivalent of roughly 6000 ft. An Oehler 35P measured the velocities and adjusted to muzzle. The target was set at 1510 yards. I used Berger's published G7 in the program. Two shots with each rifle were taken quickly followed by one shot each rifle a few minutes later. Group center was 1" high and 3" high respectively with slightly over ½ MOA for wind correction with the 300's being less. The first two shots with the 230's grouped less than 1".

Validating drop charts at a range of 1510 may not be sufficient for many with the 1" and 3" drop correction needing adjusted to true for the initial input BC. For my purposes, hunting max range around 1600 yards seems reasonable. All I can say is there would have been sufficient accuracy and precision with the Berger bullets and listed BC to hit the vitals on elk 6 of 6 shots……during validation! When conducting drop validation with other manufacturer's bullets with advertised BC's, I'd be lucky to even hit the target at 1510. Just saying!

 

[C.O. Shooter]

Mr. Courtney,

I am curious what it is you do for a job and your accolades? Is this your profession or hobby. I'm not trying to insult! I'm trying to understand. I'm sure you forgot more than I'll ever remember!

 

[cohunter14]

Predicting drop is one goal of having accurate BCs. Depending on the application, accurate BCs are also important for accurately predicting wind drift and retained energy/retained velocity.

Yes, wind drift is the other piece of the puzzle on BC's. So again, isn't having a bunch of people out shooting these bullets in real world conditions and verifying the BC better than a scientific compulation of it? Yes, things can vary and some scopes might not track properly, but that can be measured. Most good shooters check that before shooting at any substantial range.

Here is an example of what I am saying. Take the .308 230 Hybrid of Berger's through a 300 RUM at 2,900 fps. I know a lot of people have used this combo and have shot it to some extreme distances, so it should be a good example. Using Berger's G1 BC of .743, here are the results:

5,000 feet altitude, 45 degrees, 10 mph crosswind at 3 o'clock.

1,000 yards: 223.4" of drop, 42" of wind drift
1,500 yards: 652.8" of drop, 105.7" of wind drift

If you take that same bullet and reduce the BC by 8%, as you say most are off by at least that, you get a G1 of .684. Here are those results:

1,000 yards: 230" of drop, 46.5" of wind drift
1,500 yards: 687.5" of drop, 118.2" of wind drift

My point is that those changes are drastic and definitely measurable. At 1,000 yards, you have got a difference of 6.6" of drop and 4.5" of wind drift. At 1,500 yards, those numbers go to 34.7" of drop and 12.5" of drift.

This is just an example, but it shows that 8% is a drastic change. With how many people are out there shooting these bullets well beyond 1,000 yards and justifying the BC, I think it is going to be difficult to find a way to say that these numbers are off by that much, no matter what testing you do. All that really matters is real world results.

 

[cohunter14]

FWIW, I conducted drop validation on two Berger bullets three weeks ago, the 230 Hybrid and 300 Hybrid. MV was in the 3100's and 3300's respectively. Twit was 1-10 for both rifles with a DA equivalent of roughly 6000 ft. An Oehler 35P measured the velocities and adjusted to muzzle. The target was set at 1510 yards. I used Berger's published G7 in the program. Two shots with each rifle were taken quickly followed by one shot each rifle a few minutes later. Group center was 1" high and 3" high respectively with slightly over ½ MOA for wind correction with the 300's being less. The first two shots with the 230's grouped less than 1".

Validating drop charts at a range of 1510 may not be sufficient for many with the 1" and 3" drop correction needing adjusted to true for the initial input BC. For my purposes, hunting max range around 1600 yards seems reasonable. All I can say is there would have been sufficient accuracy and precision with the Berger bullets and listed BC to hit the vitals on elk 6 of 6 shots……during validation! When conducting drop validation with other manufacturer's bullets with advertised BC's, I'd be lucky to even hit the target at 1510. Just saying!

LOL, you typed this up right as I made my last post. Exactly what I was talking about though.

 

[Michael Courtney]

If you take that same bullet and reduce the BC by 8%, as you say most are off by at least that, you get a G1 of .684.

I have not said that most Berger bullets are off by at least 8%. I said most of the ones we've published our measurements on are off by that much. I have an open mind regarding the accuracy of Berger's BCs that we have not measured.

You're right that with careful attention to enough details, at some point BC errors will show up in drop predictions. But you probably aren't really measuring drop below the line of sight, you are measuring the scope adjustment needed to correct the drop between two distances. Also, we would tend to reject BC measurements based on altitude and temperature, even when using the more accurate near and far velocity measurement method or near velocity and time of flight.

At a given altitude and temperature, air density can change by 5% or more due to changes in humidity and barometric pressure. For this reason, the most dependable BC measurements measure all the ambient conditions directly (air pressure, humidity, and temperature) and compute the most accurate air density possible to yield BC measurements good to 1% or so. A 5% error in air density will contribute a 5% error in the ballistic coefficient. Carelessness with this and a host of other essential details is why drop based BC inferences are widely rejected.

 

[mitch260]

Michael,

It seems to me that you are making some pretty bold statements that contradict the findings of widely respected companies and individuals on this forum with out having established some sort of credibility or reason for us to believe you over them. I'm not saying your completely wrong, but why should we take your word over Bryan's or Berger's? Please explain to us your BC testing methods. What Chronographs do you use? You should also come up with some proof to back up some of your statements regarding the BC of some of Berger's bullets. Also, do you have a degree of some sort of education in the field of Aerodynamics/Ballistics?

Until then, I'm defiantly with Bryan on this one.

 

[cohunter14]

Michael, first and foremost, I appreciate you keeping this debate friendly, as I have had no intention of it being otherwise. The one thing I want to point out is that you did say this earlier in the thread:

One may further consider that our independent measurements of Berger ballistic coefficients has consistently yielded BCs 8% to 15% below Berger's published values.

It sounds like you haven't shot the 230's yet, but that seems to be a blanket statement that would lead people to believe it was meant about every bullet.

While I understand that certain things can affect the measurement of the BC, including the altitude, temperature, etc along with potential flaws in a scope, using your method could produce the same thing, right?

We use the near and far velocity method with chronographs calibrated to be accurate within 0.1%, chronograph separation measured with a tape measure accurate to within 3 inches, environmental conditions determined with a Kestrel 4500, and the JBM ballistics calculator.

You have measured the accuracy of the chronographs, but then again couldn't the Kestrel be off? My argument would simply be that there are always 'potential' errors out there with any sort of equipment. But, when there are a number of people who shoot Berger bullets (not just the 230 I should add) and they verify the BC's based on drops and windage out to 1,000+ yards, isn't that a better measurement than any scientific method out there? Having multiple people verify a BC by shooting a bullet at extensive distances would mean more to me than a 'scientifically correct' BC that is done by one party.

Like I said earlier, I would rather have a BC that is accurate with drops and windage than one that is 'scientifically accurate,' but will not match up with my ballistic program, and therefore my drops and windage are off.

 

[Michael Courtney]

It sounds like you haven't shot the 230's yet, but that seems to be a blanket statement that would lead people to believe it was meant about every bullet.

We have begun work with the 230 grain bullets, but we are not allowed to release results until they have been approved for public release. There is a process of peer review and review to confirm no confidential information is being released.

While I understand that certain things can affect the measurement of the BC, including the altitude, temperature, etc along with potential flaws in a scope, using your method could produce the same thing, right?

The chronographs are checked both before leaving the lab and also calibrated in the field immediately before use to an accuracy of 0.1%. 0.1% errors in the velocity measurements might yield errors of 0.5 to 1% in the BC determinations. Most bullets have larger shot to shot variations in BC.

You have measured the accuracy of the chronographs, but then again couldn't the Kestrel be off? My argument would simply be that there are always 'potential' errors out there with any sort of equipment.

As experimental scientists who expect our work to be subject to very thorough peer-review processes prior to publication and whose reputations ride on the accuracy and repeatability of our published work, experimental accuracy is an issue with which we take great care.

The Kestrel 4500s we use are calibrated at the factory to NIST traceable standards. They are regularly checked in the lab against quality instruments and against each other, and they are checked against each other in the field. We've been using them for many years and are happy to report that they consistently meet their pressure accuracy spec of typical 0.04 inHg and a max of 0.07 in Hg as well as consistently meeting their temperature and humidity specs. A possible inaccuracy of 2.3 parts per thousand in pressure would translate into a BC inaccuracy of less than 0.3%. A worst case scenario where the temperature, humidity, and pressure are all on the edge of the accuracy spec still translates to a BC inaccuracy of less than 0.5%. Potential errors exist with all equipment, but we've found the Kestrels to be reliable and any errors they might introduce to BC measurements are minimal.

The attached picture shows three Kestrels side by side. In a perfect world, they would read exactly the same to all four significant digits. The older unit on the left that has provided many years of service is reading low by 0.04 or 0.05 in Hg. This 0.17% error would yield a BC error that is 0.17% too high.

As a final check on system accuracy, we also always measure the BC of a standard bullet which we have found to give the same BC under many different conditions and circumstances over time. Any error with the chronographs, spacing, or environmental measurements would show up in the BC determination of this standard bullet. It never has.

 

[cohunter14]

Michael, while I appreciate your response and your effort to minimize any sort of error in your work, I think you are still missing my point: if there are thousands of very experienced shooters on this forum who are shooting any number of different Berger bullets out well passed 1,000 yards and the BC's are proving to be true for each of them, how can you dispute that? If you plug the number into your ballistic calculator and the drops and windage match up with the BC you are using, how can it be wrong? If Berger was consistently off by 8%-15% on their BC calculations, don't you think that would show up in these results?

Simply put, I think you have one heck of an uphill battle to prove your numbers are correct versus the thousands of people who have seen the actual results of the bullet. Again, I don't care how the BC is determined, as long as it works when I plug in my numbers. And how can it be wrong when you plug it in and the bullet goes exactly where it is supposed to?