Personalized Drag Model's Become a Reality

[DocUSMCRetired]

The AB Mobile Lab has now seen half a dozen events, and this time we changed the game. At the Precision Rifle Expo each of our team members was not only able to give a class but we performed a public demonstration of the Mobile Lab's ability to upload Personalized Drag Models from the field. Users were able to shoot their rifle and within a short period of time download that rifles PDM via the AB Connect System and use it. In many cases before the demonstration was even over their PDM was already live and ready to use. This was further demonstrated when shooters like Mitchell Cox from Barrett were able to get a PDM on the spot, and turn around using that PDM to get a 1st round hit with factory Berger Ammunition at 2125 yards with his own rifle. He stated that he had never shot beyond a mile before that.

We were able to upload 12 PDMs during the live demonstrations/classes throughout both days. PDMs for AB Training Division, Barrett, Burris Optics, Chase, Corbin Shell, Pierce, Stiller Actions, Vudoo Gun Works, David Lott, Brian Wink and more.

We will be bringing the Mobile Lab back out for the Kestrel Fall Classic and doing PDMs for users on Zero Day before the match. Anyone is welcome to stop by and see it in action. But AB will now be providing an unmatched level of precision drag modeling by allowing users to use their rifle and ammo loads under radar.

Our PDMs are tracked through transonic into subsonic so they are valid for ELR Shooting, and do not suffer from the variances that G1 and G7 have.

 

[garandman]

"drag models" Generated a totally different picture in my mind...

 

[Tommie]

“Mommy, I learned about drag models on the internet today”

 

[garandman]

^ ^ ^ lol

 

[D.Stone]

What variance between personal drag models and custom drag models have you seen?

 

[Dusty Stevens]

Very cool.... but i sure did have a different image in mind

 

[thejamesd]

I'm not gonna Goggle that!

 

[rwj]

Very cool.... but i sure did have a different image in mind

I hope they chose to use the PDM acronym!

 

[joshb]

Very cool.... but i sure did have a different image in mind

Still can’t get that pic out of your mind? Me either. First thing I thought of when I saw the post.

 

[Intheshop]

Jungle Pam(Hardy) popped into my pea brain.

 

[Dusty Stevens]

 

[DocUSMCRetired]

What variance between personal drag models and custom drag models have you seen?

This is something that is harder to determine because many shooters do not know the lot numbers of the bullets they tested. Some do. So its still an ongoing study.

 

[garandman]

@Dusty Stevens .... that your personal drag model?

OK...seriously..... I'm not googling it either.

What is a "personal drag model?" Something to do with interior / exterior ballistics?

 

[DocUSMCRetired]

@Dusty Stevens .... that your personal drag model?

OK...seriously..... I'm not googling it either.

What is a "personal drag model?" Something to do with interior / exterior ballistics?

You have BCs (G1, G2, G5, G6, G7, G8, R4A, Gsp....) Which means you take a known model, and then attempt to predict your current bullets flight by scaling. However you are assuming that it will perform the same at high, medium, transonic, and subsonic speeds.

You have CDMs. Which means you are not using a BC at all. Instead you are modeling the actual bullet in flight and just using that. Out of a standard test rifle. Of course no two rifles are the same. People use different twist rates, muzzle devices (suppressors, brakes, tuners), different rifling (4, 5, micro, gain twist), chassis vs railgun vs stocks, etc.... So variations do exist which can have an impact on the bullets. You also can have (some manufacturers are very good about minimizing the changes) variations in bullets from lot to lot as the dies are replaced.

Then you have a PDM. Which means that you take a specific users rifle, and ammunition load, bullet lot, etc. and you simply fire that rifle over the radar system. You take an average (say 10 - 15 shots) and use that to compile a drag model with that users own setup. So the bullets flight prediction model is directly from that users system, and is compiled from live fire data.

Basically with a PDM a user gets to take the real world radar measured flight and input it into the system for predictions.

You can read more here: http://appliedballisticsllc.com/ballistics-educational-resources/custom-drag-curves/

 

[garandman]

Thanx @DocUSMCRetired .. .. I will check it out.

 

[fyrewall]

Is that a real woman? - sort of excessive for my tastes. Looks tough.

Would Hornady's 4DF program approach this with Doppler radar data for specific bullets using specific velocities, twist rates, and environmental data?

 

[DocUSMCRetired]

Is that a real woman? - sort of excessive for my tastes. Looks tough.

Would Hornady's 4DF program approach this with Doppler radar data for specific bullets using specific velocities, twist rates, and environmental data?

PDMs are not velocity specific like a BC is. Also the environmental data is a non issue. We set the CDMs and PDMs to standard atmosphere.

 

[fyrewall]

PDMs are not velocity specific like a BC is. Also the environmental data is a non issue. We set the CDMs and PDMs to standard atmosphere.

The Hornady 4DF stuff does not reference BC's but considers velocity as per the Doppler data and makes allowances for environmental conditions. Would this be appropriate for real world use?

 

[DocUSMCRetired]

The Hornady 4DF stuff does not reference BC's but considers velocity as per the Doppler data and makes allowances for environmental conditions. Would this be appropriate for real world use?

Without knowing the distance the data was tracked to, it is hard to say. The key zone being the transition into subsonic. If a bullet is tracked only through supersonic then the rest of the data has to be extrapolated instead of measured. If it is tracked into subsonic for the specific bullet in question than yes. We were tracking rimfire bullets to 850 yards (well through the transition into subsonic for supersonic rimfire) and we were tracking centerfire to beyond 2K which means we did get the transonic data on it. In those cases, its very solid data. So without seeing the entirety of it, I cannot really answer that without speculation.

 

[JFrank]

View attachment 1129647

That shade of lipstick is totally wrong