Using a Labradar and a couple of bits of information to determine bc.

[Healthservices]

So I finally got a Labradar, although still learning to use it. Since BC is different depending on the speed of a projectIle, I guess the average BC for a shot over a particular distance is what is desired correct?
With some other measurements other than distances and speeds, from altitude, air density, humidity, projectile shape, and other factors (more the better?) I can generally determine the the average BC for a particular distance if shot at a starting speed, right? What formulas or apps are you guys using with the data from the Labradar?

So far I have found this online.

JBM - Calculations - Ballistic Coefficient (Velocity)

www.jbmballistics.com

Thanks

Allen

 

[JungleShooter]

Hi Healthservices,

for BC calculations using the airgun drag model GA we have two to choose from:

▪ ChairGun for Windows [the mobile version is just a skeleton of the Windows version] (discontinued, but still available for download from the Hawke website)

▪ GPC Ballistics Applications
A full suite, for Windows, Android, iOS, Linux — so you can do desktop, or mobile in the field, very nice.
Link:

GPC Ballistics Applications

Both are free.

You enter the starting and ending velocities and the range, and get a single BC number — just like if you only had two chronos.


➔ But with a labradar you could get a lot more precise BC numbers over the full range of velocities.

For that.... on the GTA forum there is Bob Sterne (aka rsterne) and a professional ballistician, Miles Morris (aka Ballisticboy).
They will probably have spread sheets and advice on how to transform a whole data dump into a custom drag model (CDM).


In reality, the BC normally is constant, and what changes is the drag model (it's a curve). But since the drag models for our pellets are so far removed from reality (one size never fits all...) — we end up having a variable BC number — depending on the projectile's velocity...


Please, share your BC research!

Matthias

 

[Healthservices]

Thanks, I've been moving toward slugs as of late but will post what numbers I have as I learn to use the Labradar.

Allen