Future of Ballistics Apps?

[DocUSMCRetired]

We recently attended the Worlds Longest Shot Challenge, where our team took 1st, 2nd, and 3rd place in the Over 338 class. We did this using a bullet that had never been fired beyond 1000 yards before the event. By the end of the event, that bullet design had hit a target at 2 miles. There are actually 2 prototype bullets and both placed in the top 3 at this event. The Berger 375 Solid Prototypes.

At this event we setup a mobile ballistics lab along with the help of Ken Oehler. With Radar and the 88 system being used at 2400 yards shooters were given the chance to fire over both system and get print outs of the general data. Taking this one step further, we had the ability to compile the data and push to the apps via AB Connect™ right there in the field.

One of the shooters at the comp took the ammo we had loaded for a rifle (not tuned for his rifle) shot 5 shots over the Radar, then checked zero, and got a 1st round hit at 2 miles.

Just sharing all this to give something to think about. We do plan to attend more events, and we are not against setting the system up again. Is the future of ballistics app where you select your own Personalized Custom Drag Models from the library instead of a manufacturer and bullet? Who knows, but the results were incredibly promising.

 

[370bc]

Yikes that’s Awesome stuff! My kind of an amusement park!

 

[pat fulghum]

"Took the data... and got a 1st round hit at 2 miles".... HOLY COW!

That is awesome. Is that a 36 inch square plate at 2 miles?

My calculations show that a 36" plate at 2 miles (3,520) yards is 1 MOA.

 

[Ballisticboy]

I have been involved in trials on rifle bullets for some years now using various tracking radar systems to track bullets out to ranges from 2 to 6 km depending on the bullet calibre and type. We have used fixed head doppler radars similar to the one being used here to measure muzzle velocities, the main tracking data being obtained from a doppler tracking radar with a moving head. My back ground is in large calibre artillery weapons where we always use two fixed head dopplers to measure muzzle velocities. I carried this practice over to the small arms where we immediately found out it is very difficult to get the two radars to agree. The difference in muzzle velocities could be anything from 3 to 10 m/s, way outside the requirement of less than 1m/s. The problem lay in the positioning and aiming of the radar heads which is critical for bullet tracking. Minute changes could make large differences.
I have also been using the data from the fixed head systems to produce drag data to supplement the data from the main doppler tracking radar used for the majority of the trajectory. The data from the fixed head radars is often at odds with the data from the main radar.
Looking at the setup in the pictures I would say that the radar appears to be too far away from the rifle for accurate data. I know these radars have a wide beam width but our experience suggests they are very dependent on the relative positioning of the gun and radar. Positioning the radar much closer to the gun will allow the bullet to enter the beam much sooner and reduce the guesswork in the software in trying to fit a curve to the data to produce an accurate muzzle velocity figure.
I hope you find the above of interest.

 

[Capt. Oblivious]

Awesome!!!

 

[wi50]

I'm curious on the "first round hit". Is a first round hit where a shooter fires a round and connects with the target all on his own with nothing other than the data they have from an attempt several hours before? Or is a first round hit where two or more rifles were fired in series where the first shooter slings bullets and gets data, the next shooter has that information and can make the correction for his rifle and then commences fire to make contact with the target?

 

[LA50SHOOTER]

I have been involved in trials on rifle bullets for some years now using various tracking radar systems to track bullets out to ranges from 2 to 6 km depending on the bullet calibre and type. We have used fixed head doppler radars similar to the one being used here to measure muzzle velocities, the main tracking data being obtained from a doppler tracking radar with a moving head. My back ground is in large calibre artillery weapons where we always use two fixed head dopplers to measure muzzle velocities. I carried this practice over to the small arms where we immediately found out it is very difficult to get the two radars to agree. The difference in muzzle velocities could be anything from 3 to 10 m/s, way outside the requirement of less than 1m/s. The problem lay in the positioning and aiming of the radar heads which is critical for bullet tracking. Minute changes could make large differences.
I have also been using the data from the fixed head systems to produce drag data to supplement the data from the main doppler tracking radar used for the majority of the trajectory. The data from the fixed head radars is often at odds with the data from the main radar.
Looking at the setup in the pictures I would say that the radar appears to be too far away from the rifle for accurate data. I know these radars have a wide beam width but our experience suggests they are very dependent on the relative positioning of the gun and radar. Positioning the radar much closer to the gun will allow the bullet to enter the beam much sooner and reduce the guesswork in the software in trying to fit a curve to the data to produce an accurate muzzle velocity figure.
I hope you find the above of interest.

The U.S. Navy has been using Doppler Radar in the MK 15 CIWS (Close In Weapons System) anti-ship missile 6 barrel 20 mm Gatling guns since the late 1980's - The radars (it has a search acquision & a tracking modes) actually track the depleted uranium projectiles as they are in transit to the air-born flying target as well as the in-bound bogie. - The technology (both hardware & software) has been around for years & in use by military forces all over the world. - I did 15 yrs on active duty as a missile fire-control technician in my earlier years. (first career)

 

[dcali]

I have been involved in trials on rifle bullets for some years now using various tracking radar systems to track bullets out to ranges from 2 to 6 km depending on the bullet calibre and type. We have used fixed head doppler radars similar to the one being used here to measure muzzle velocities, the main tracking data being obtained from a doppler tracking radar with a moving head. My back ground is in large calibre artillery weapons where we always use two fixed head dopplers to measure muzzle velocities. I carried this practice over to the small arms where we immediately found out it is very difficult to get the two radars to agree. The difference in muzzle velocities could be anything from 3 to 10 m/s, way outside the requirement of less than 1m/s. The problem lay in the positioning and aiming of the radar heads which is critical for bullet tracking. Minute changes could make large differences.
I have also been using the data from the fixed head systems to produce drag data to supplement the data from the main doppler tracking radar used for the majority of the trajectory. The data from the fixed head radars is often at odds with the data from the main radar.
Looking at the setup in the pictures I would say that the radar appears to be too far away from the rifle for accurate data. I know these radars have a wide beam width but our experience suggests they are very dependent on the relative positioning of the gun and radar. Positioning the radar much closer to the gun will allow the bullet to enter the beam much sooner and reduce the guesswork in the software in trying to fit a curve to the data to produce an accurate muzzle velocity figure.
I hope you find the above of interest.

That's interesting. Any thoughts on how much it matters that the muzzle velocity be exactly correct if you are primarily concerned with obtaining a cd vs mach table? How much uncertainty are we talking about in the overall drag function with one of these units?

 

[Ballisticboy]

That's interesting. Any thoughts on how much it matters that the muzzle velocity be exactly correct if you are primarily concerned with obtaining a cd vs mach table? How much uncertainty are we talking about in the overall drag function with one of these units?

The accurate value of the muzzle velocity is not very important for the production of the drag curve. It will only affect the first few values depending on the exact method being used in the computation of the drag coefficient. However the muzzle velocity differences did show up how much the data from the two radar sets could vary from each other.
Part of the difference lay in the number of data points each set obtained and the form of the curve fit chosen by the software for each radar unit. Of more concern in many cases was the shape of the derived drag curve which was not realistic and did not blend in with the drag curve derived from the data from the large tracking radar used for most of the trajectory.
As for the error size, I have seen differences between the measured muzzle velocities using two fixed head radar sets of up to 20m/s in a muzzle velocity of 350m/s on a 9mm projectile. In a test many years ago on a 14mm low speed projectile errors of 10m/s in a muzzle velocity of 110m/s were seen using a single radar head. I first suspected the measured values were not accurate when I needed a negative drag coefficient to match the measured range of the projectile. Subsequent testing of the same gun showed up the error. The error in measured velocity will directly affect the calculated drag value and the velocity changes.
Atmospheric affects such as wind etc. will also introduce errors. On one trial I compared a radar computed drag curve which just uses the radar data with a fully analysed value using full atmospheric data. The errors on that occasion coud be as high as +/- 5% depending on the wind direction.
As I said my back ground is in range and accuracy (R&A) trials for large calibres where the accurate measurement of muzzle velocity is vital. That is why I carried over the use of multiple fixed head radars for muzzle velocity to small arms even though it is not so important. The use of multiple fixed head radars along with fully tracking radars for large and medium calibres has been widespread since the 1960's when Mach number drag curves were first used for fire control systems to give accurate fire control data. The data from R&A trials has to be of the highest quality possible as it is used as the basis for the fire control for the guns for the next 10-20 years and thus the systems used have to be much more accurate than in service systems used by the forces.
The tracking of a projectile of 20mm or 155mm is much easier than trying to use those same systems on a 5.56mm bullet. Clouds, weather fronts and all sorts of atmospheric conditions can easily wipe out the radar reflection causing the radar to loose the track or give false data. Extreme caution is needed in the setup and use of these systems if errors are to be avoided.

 

[dcali]

The accurate value of the muzzle velocity is not very important for the production of the drag curve. It will only affect the first few values depending on the exact method being used in the computation of the drag coefficient. However the muzzle velocity differences did show up how much the data from the two radar sets could vary from each other.
Part of the difference lay in the number of data points each set obtained and the form of the curve fit chosen by the software for each radar unit. Of more concern in many cases was the shape of the derived drag curve which was not realistic and did not blend in with the drag curve derived from the data from the large tracking radar used for most of the trajectory.
As for the error size, I have seen differences between the measured muzzle velocities using two fixed head radar sets of up to 20m/s in a muzzle velocity of 350m/s on a 9mm projectile. In a test many years ago on a 14mm low speed projectile errors of 10m/s in a muzzle velocity of 110m/s were seen using a single radar head. I first suspected the measured values were not accurate when I needed a negative drag coefficient to match the measured range of the projectile. Subsequent testing of the same gun showed up the error. The error in measured velocity will directly affect the calculated drag value and the velocity changes.
Atmospheric affects such as wind etc. will also introduce errors. On one trial I compared a radar computed drag curve which just uses the radar data with a fully analysed value using full atmospheric data. The errors on that occasion coud be as high as +/- 5% depending on the wind direction.
As I said my back ground is in range and accuracy (R&A) trials for large calibres where the accurate measurement of muzzle velocity is vital. That is why I carried over the use of multiple fixed head radars for muzzle velocity to small arms even though it is not so important. The use of multiple fixed head radars along with fully tracking radars for large and medium calibres has been widespread since the 1960's when Mach number drag curves were first used for fire control systems to give accurate fire control data. The data from R&A trials has to be of the highest quality possible as it is used as the basis for the fire control for the guns for the next 10-20 years and thus the systems used have to be much more accurate than in service systems used by the forces.
The tracking of a projectile of 20mm or 155mm is much easier than trying to use those same systems on a 5.56mm bullet. Clouds, weather fronts and all sorts of atmospheric conditions can easily wipe out the radar reflection causing the radar to loose the track or give false data. Extreme caution is needed in the setup and use of these systems if errors are to be avoided.

Thanks. Very good stuff. So would you say that for a single fixed head radar used at a typical rifle range out to, say, 1500 yards, would result in drag coefficient error in the +/- 5% range?

 

[Ballisticboy]

Thanks. Very good stuff. So would you say that for a single fixed head radar used at a typical rifle range out to, say, 1500 yards, would result in drag coefficient error in the +/- 5% range?

Difficult to say as it will depend on the atmospheric conditions, the amount of atmosphric data and the care with which the instrumentation has been set up. The significance of the error will also depend on its use. For example, take the test which is the subject of this thread. If the atmospheric conditions were not measured then the values of Cd would be wrong, but they will still work on that day at that place if the same assumed conditions are input into the trajectory model. The values obtained would not be correct for other days at other locations where the air density and wind may be different. This is why when we were analysing data from our trials all the conditions were corrected to standard values so that the data could be used under any known conditions. If comparing projectile performance it is also of course important to use standard consistant conditions.
Under the conditions we were testing in it was very unusual to obtain a good track out to 1500 yards with a fixed head doppler depending on the calibre being fired. Some would be as short as 200 yards though it does depend on the quality of data you are prepared to accept. We were using data from a multimillion dollar tracking radar for those ranges. There is also the effects of trajectory curvature to be taken into account at the end of the trajectory which will only be measured using a tracking radar or by measuring drop on a target.
With careful measurement and control of the conditions by only firing under favourable met, the errors can be around +/- 1% assuming a robust analysis method. At other times then +/-5% is probably more realistic depending again on the conditions. But, as I said before, the significance of the error will depend entirely on the use of the data.