Hornady 4DOF Inside Look by Sniper’s Hide

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Want to know more about the Hornady 4DOF Solver ? Go behind the scenes and get an inside look at the Hornady Doppler Unit and the Results with Sniper’s Hide.

Hornady Doppler Radar and 4DOF Solver


Recently there was some drama in the forums and online in general regarding the new Hornady 4DOF solver. Much of the details were reduced to “Marketing Hype” so in order to give an outsider’s perspective on the work being conducted, I was invited out to Hornady by Chief Ballistician Dave Emary.

Hornady is only 5 hours away by car, so it was an easy choice to make. Of course I wanted to see what they were doing.


hen I arrived at the Hornady I was met by Dave and Jayden Quinlan who are in the ballistics department at Hornady. No marketing, or sales people were there to greet me. First thing on Tuesday morning Dave and Jaden had a conference call to attend, so they handed me over to Michelle for a complete tour of the factory.

Factory Tour

Hornady employs close to 700 workers at their Grand Island plant, and Michelle escorted me through the entire facility. Dave was kind enough to give me the clearance to see some things that are not on the normal tour. We checked out everything from the testing labs to the brass fabrication. It’s nice to stop by and talk to the person making the 6.5 Creedmoor ammo. As much ammo as being loaded, watching it get hand checked is something you don’t expect. I was amazed how many times brass is washed as it takes a month long journey from button to finished product. To say Hornady is huge is an understatement, one section of the factory used to be the employee parking lot to give you an idea. It’s big, with just about everything from lead smelting to tool making it done in house. It was even cool seeing the Bartlein Barrel test fixture in the ranges, I was like, “Hey I know those guys”. Neat stuff

Once the tour was complete, I met back up with Dave and Jayden for a presentation and explanation of the ballistic work being done. They had prepared a powerpoint with a brief background, as well as details so I would better understand what they were seeing. This was to be an open discussion, so nothing was off limits. In their view they wanted to educate, it wasn’t about hyping the 4DOF solver. They had a binder of the slides as well as a thumb drive of the actual presentation available for me. What I saw, I am passing on.

Ballistics Background


We started off with the basics, what we need to know in order to predict what our bullets will do downrange. In short we need to know how fast it slows down, that is a function of Shape, Area, Mass, Velocity, and Air Density. We talked history and the most basic differences between the Point Mass Code and the 4DOF Modified Point Mass Code. Part of the historical background information included information on Chronographs, how they really haven’t changed since the 1940s. Even though the technology has improved, the assumptions remain the same when it comes to predicting bullet drop. Many don’t realize the G7 standard has been around since the 1940s. It was during the 1940s that G7 projectiles were tested and that curve is still the same one we use today.

After 200 years very little has changed

Why BCs

They addressed “Why BC’s”, the short answer is, they are simple and for the average shooter working inside 600 yards it was good enough. Now that we are shooting farther than ever before, their limitations are becoming evident.

People are asking online, “Why no BCs in the Hornady 4DOF Solver

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If you look at a lot of the historical data in the books out there on Ballistics, much of it was referenced inside 600 yards. Even in Dr. Arthur Pejsa’s book, New Exact Small Arms Ballistics, he talks about working with the Point Mass Code between 400 and 500 yards and how changes were necessary to go past 600 yards. It took a long time for people to extend their thinking beyond 1000 yards. Most of this was designed around the hunting crowd shooting inside 400 yards. So you can see where this would be a problem today.
From here, we talked about the limitation of truing a BC and the mismatching of Mach Curves and Cd Curves. It’s the same discussion we often have with G1 vs G7, but expanded to include Mach Curves vs Cd Curves. Using a BC means velocity is a critical factor. With the use of Doppler Radar they can now map and see these differences. Not just in the curves but with different cause and effect situations a bullet encounters. In the Hornady Technical Paper you can see the variations with muzzle brakes, powders, twist rates on the curve.

As noted in my post in the Sniper’s Hide forum, the 4DOF of freedom paper was written in 1966. This is available on the internet and recognized limitation in the standard 3DOF code. Hornady moving to this over the more common 3DOF code is a recognition of the potential gains by adding Pitch and Yaw.

Angle of Attack


A lot of pilots are long range shooters, and they will tell you Angle of Attack Matters. The 4DOF model takes into account this angle of the bullet as it moves through the air. Not just that, but the changes in center of pressure as the bullet slows down. All this helps them model the drop and drift of the bullet, especially at extended ranges. It is understood this is a bit more work, and not as simple a solution as a 3DOF Point Mass solver.

I recommend downloading and viewing the Hornady Technical Paper that was written for the release of the 4DOF Solver, they go into much more details than I plan on writing here. I can certainly get into the weeds, but the who would read this. Their technical data helps us understand the pros and cons of a solver as well as the limitations of each method.

In discussion of this trip with others, it was noted, we now have 3 different methods of determining the same information and none of them agree. You can say we are splitting hairs, but this is the internet and something we excel at.

Personally, seeing the work being done by Hornady I have to say, it appears to be right approach. I have made no secret of the fact I support ColdBore 1.0 and TRASOL, both with the Patagonia Ballistics Engine. The work being done by Hornady mirrors a lot of what I respect about the Patagonia approach.

While you can say all methods have some amount of assumption and interpretation, this is basically less than 5% of the big picture. They are accurately gathering much more data, and guessing at a lot less of the equation. This is me putting it in layman’s terms.

The rest of the afternoon was spent comparing my saved data from all the solvers in my possession to the Hornady 4DOF solutions. We had the online version of the 4DOF solver on the big screen, and I randomly sampled my verified data. The variations were too small to mention. I pulled saved data from Ballistics AE, ColdBore, TRASOL, Applied Ballistics, each track was compared out to subsonic distances. Sure it was a bit of time killer but it was important to use my data, this eliminated the chance of being hyped or marketed. It was my confirmed data, it wasn’t cherry picked. After all, confirmed real world data is the end game. Who cares what the computer says, if it doesn’t match our results on the ground it’s just a waste of time. From this perspective, the Hornady 4DOF solver was spot on.

On The Range

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Hopefully by this point you have read the PDF Data, if not, stop here, read it, and come back.

On Wednesday we hit the range using my rifles. I brought a Ashbury Precision Ordnance ASW300MW, of which Hornady loaded up 212gr Ammo. The day before inside the building we did a simple chamber check, did the bolt close, yes, good enough. I also brought my Accuracy International AX and AW rifles. Both rifles using 6.5 bullets. I also brought my confirmed Lapua Loads with the 139gr bullet, and 136gr bullet. As well over the weekend I loaded up some 140gr ELDs for my 260REM using some basic data I found in the Sniper’s Hide Forums. 42.3gr of H4350, loaded to 2.810. Never shot them, have no clue, it was the most common load I saw in the forums, so I ran with it.

Conditions the Morning of the Shoot

Barometric Pressure: 27.77

Temperature: 55 degrees

Humidity: 82%

The Infinition Doppler Radar unit was set up to record data as far as possible. This was there to give me an idea of the methods used to track the bullets in the library. Hornady is doing real world tracking of bullets. So the library while small today, it will grow as they add in new bullets. The plan is to definitely expand the library, covering not just Hornady bullets, but many others as possible.

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So with my rifles in hand, we tested what bullets we had on hand with the following results:

300WM 212gr Bullets read to 2220 yards

136gr Scenars read to 2100 yards

140ELDs read to 2000 yards

143ELDs read to 2000 yards

139gr Scenars read to 2000 yards

This gave us not only a model for them to use, but also an accurate muzzle velocity to plug into the 4DOF Solver. (We used the online version, not something unavailable to the public) The Cd curves noted were not used. For me, this was just reference information, the only data from the Doppler we used on the range that day was the Muzzle Velocity recorded out of my rifles.

Importance of a True Zero

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My APO ASW300 was zeroed using 220gr RUAG ammo, switching over to the 212gr bullet we needed to measure the difference. Hornady has two videos that will be coming out showing the importance of determining your zero and how to use their solver to fine tune that number. This method is also found in ColdBore. After shooting the group on paper at 96 yards, we determined my ASW300 had a 157 yard zero. No adjustment was made, only a measurement taken to determine my real world zero. The AW had a measured 96 yard zero as no change could be measured as the impacts covered the 1/4” aiming point. Understand my ASW300 zero was 5/8” high, and 3/8” to the left, no adjustment was made to the scope. We moved forward with what we had. Even a rifle assumed to have a 100 yard zero that is .25” high or low will result in a 2.5” error at 1000 yards. The idea behind the true zero range is to fine tune the predictions. It’s an area they can address so they are. With other solvers you can do the same thing or use what some call the zero offset. This is slightly different but has the same principle behind it.

That was the only prep work done, we shot the rifle across the Doppler Radar for their database, but also used that information for a Muzzle Velocity. Then we measured our Point of Impact vs the Point of Aim calculating the True Zero Range. Inputted into their 4DOF solver off the internet, (again same one available to everybody), we went straight to 1000 yards.

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Dope for both rifles as follows

1010 yards

ASW300WM – 7.8 Mils

AW w. 140 hand loads, 8.0 Mils

Next was shots at 1207 yards

ASW300 – 10.6 Mils

AW140s – 10.8 Mils

Moving to 1500 yards

ASW300 – 15.8 Mils

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Now, my AW has a S&B 4-16x Mil scope with a single turn elevation turret. It tops out at 13 mils so I needed to hold over everything beyond 13 Mils.

Using 13 Mils + a 3.3 Mil Hold I had a 2nd, 3rd, and 4th round hit on steel. Total 16.3 Mils

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ASW300 – 22.0 Mils

We shot more than one plate from a sub MOA to two larger plates and I managed 4 out of 7 hits on the plates at 1 mile. The wind was extremely tricky. We had a 1 to 7 MPH change. During the Shots, Dave was downrange with a Kestrel, and Jaden was at the Shooter with a kestrel and both were independently reading off the data. The bullets were mid flight when changes happened making it impossible to keep up. But with their Spin drift and Wind calls we found when we hit on the right speed with my break the shots impacted correctly. I find Hornady Spin Drift much closer to real life than every Point Mass calculator I have ever used. Hornady compared their data to SPARK Range information in order to model the bullet.

The 140s with AW was going to be much trickier, we needed 23.3 Mils with a scope that only dialed to 13 mils. LOL, holding wind and elevation using the Klein reticle in my S&B was going to be fun.

13.0 Dialed on, I held the 10 mil line at the bottom of the heavy post just at the top of the plate. (Measured .4 in the reticle to center) I had a 3rd, 4th and 5th Round hit then the wind changed and it was hit or miss with the rest of my ammo. We had taken the 21” 260REM out to mile with untested ammo and scored. The results out of the gate with a rifle not doped was excellent. Aside from changing the Form Factor in the 4DOF calculator to 1.02 we adjusted nothing. The Doppler Recorded Muzzle Velocity was spot on, as one might expect.

Using Hornady Form Factor

By using their software online, we determined the ASW300 had a form factor with the 212gr bullet of 1.0. This meant it was matching up to the base Curve found in their library. No changes needed. This was the real world curve they recorded with the Doppler Unit and found in their library. With my AW shooting my 140 Hand Load the Form Factor was 1.02. This meant the AW had a higher Drag than the base curve so we needed to tell the software to adjust it. You don’t true with MV, you are not using a BC, you use the Form Factor Drop Down. Find your dope is off the predicted solution, you adjust this Form Factor to True. We are not manipulating the Doppler Derived Muzzle Velocity, we just changed the Form Factor. Caveat, if your Chronograph is not one of quality, you may need to make a small adjustment to the MV, so if you are moving it a 100fps or more, something else is wrong. Remember you still have to test things like your scope, a huge source of error. These solvers only know what you tell it.

This is the way of the future. Is your real world curve faster or slower ? If so adjust the Form Factor, not the measured inputs. When comparing, the G7 curve is not exactly correct, much like the difference between G1 vs G7. The Cd vs G7 is off just enough too. They have noted that Twist Rate, Powder, Muzzle Brakes, etc could move the Cd Curve a bit, so in order to line it back up, you use the Form Factor. Simple and effective

The Doppler Radar is recording the shot in real time out to distance. We measured shots beyond 1 Mile. This is the basis for the Cd Curve used in the Solver’s Library. The Cd Curve is adjusted using ICAO so it’s not dependent on what they did, but adjusted.

I have read in several places about Hornady not providing the raw Doppler Data like Lapua originally did. That is correct, they have a significant investment in the Unit, so giving it away is not gonna happen. While they are in the business of making bullets, they have also entered the Ballistic Computer business too, so there is no benefit in feeding the competition. The online solver with its library is free, so they are giving the benefit of their work away there. Doesn’t cost you anything to use. It’s not like a Custom Curve from AB is free, that is an In-App purchase, with no $100,000 Doppler investment behind it. We all get it, there is effort on both sides that has value.

Back to form factors, you can determine the Form Factor, go to new location, drop in the Conditions and print a drop chart that already knows what your rifle is. It’s going to be much closer than any PM App out there. More and more people are seeing the limitation of manipulating the BC and MV, in most cases that is actual information you have measured. Changing the Form Factor much like with TRASOL, ColdBore, FFS, with their DK/DC function, it separates the adjustment from the measured data. I picture it like a scale, where you have your BC in one hand and MV in the other. If you add weight to the BC you raise the MV hand and vice versa, this other way you move the drag curve in a logical manner. It eliminates those sweet spots we see with standard Point Mass solvers. If you never travel very far, you might not see the limitation, but if you go from 5000ft like me, to places that are sea level, you see it. Basically I have to true all over again, usually to the tune of 50fps.

ELR Implications for Zeroing

By using their methods to fine tune your zero, you can establish a better base line for ELR Engagements. Shoot a 100 yards, impact high, determine the actual Zero range without the limitation of shooting at distance and then calculate your actual zero range. I would draw a center line for windage, however I would not care where above the 100 yard aiming point you hit. The fine tune calculation will give you the number. This method can be used with other solvers, and like I said, the issue of zeros being off has come up in other conversations on solvers. Hornady just confirmed its impact on the solution. Most people are not shooting their ELR rigs at targets inside 600 yards so who cares where your POI is at 100 yards. But zeroing at targets at 600 yards has limitations. This way you can successfully extend your range and still have solid data to work with.

I am definitely going to look at the impact of actual zero ranges vs the perceived zero range we use now. Especially if you have no interest in really shooting a target at 100 yards. I was even considering aiming at 6 O’Clock on a small circle, impacting in the dot and measuring my offset to use. That way for competition you have a fine aiming point, the edge to use. My group with the 300WM was only about 3/8” from center, that changed my zero range to 157 yards. Where inside that 1” circle aiming point we use matters. The same accuracy we use to measure group size will now be used to measure POA vs POI in the context of our zeros. The software can manage it, so why not use it.


Sniper’s Hide

This trip was illuminating on so many levels. It confirmed a lot of what I debated on the internet for years. It reinforced what I already knew, and it opened my eyes to different methods. With improved technology it only makes sense to improve the assumptions and tighten up our predictions. Using new technology with old data only tells me that two wrongs don’t make a right. If G1 is wrong, well so is G7 to about the same degree. The dependence on the G system (BCs) is a bit outdated if you ask me. It’s why some days G1 lines up better and other days G7 does. Besides being velocity dependent, it’s also determined by our system which requires a lot of manipulation to work. I have stated many times the goal should be to true less and have better real world results. Real World Curves make for better real world results. Anybody can fudge data until it matches, trial and error is easy if you have the time and energy. But most of us are looking for a better solution with less trial and error effort.

Hornady is on the right path, that is not to say anyone else is wrong, it’s just a different means to an end. We already know inside 1000 yards most of what we use works, it’s beyond that distance we need to tighten things up. If you only shoot to 1000 yards it doesn’t really matter which solver you use. The free one, the online version, the App with brand recognition, all will give you success to varying degrees. I feel Hornady recognizes the changes of time and are accounting for them to the best of their ability. It’s been said by others that Doppler is the standard we should all strive for, Hornady just heard that and responded. It’s really a hype free approach.

After reading this, take a second look at the Hornady Technical Paper on their work and draw your own conclusions. Recognize here, they let me film what they were doing and then ask yourself what reading a real world shot to 2000 yards can help you accomplish vs modeling something based on a 300 yard BC number.

These were the facts of the trip.

I appreciate the invite, I want to Thank Dave Emary and Jayden Quinlan for the hospitality as well as Tab and Lonnie for the range help. This was educational, fun, and worth every minute. Not once was I Hyped, there was no sales pitch, it was presented straight forward with no bias. I was allowed to draw my own conclusions and in places where my other solutions matched the Hornady solution, they said nothing derogatory about it.