I have 5 B.C.'s for my bullet. Which one to use?

[MarikinaMan]

Hey.

From using a ballistic app and a magneto speed, I am incorporating a Kestrel Ballistic computer and rangefinder (for truing and less dependent on the distance provided at the range).

I used to use the manufacturers B.C. but now, I have access for different B.C. data.

For example, on my Hornady 75gr BTHPs (.224) I have the following:

Hornady G1 - 0.395
Litz G7 - 0.283
Kestrel G1 - 0.348
Kestrel G7 0.179

The Hornady data gets me first round hits, but not all the time. I feel its not great with wind.

For the Hornady 140gr ELD M (.264) I have the following:

Hornady G1 - 0.646
Hornady G7 - 0.326
Ballistic AE G1 - 0.610
Kestrel G1 - 0.568
Kestrel G7 - 0.291

I'm inclined to use the G7, coz these are BT's.

My questions is, how do you figure which source to use?

I guess if I’m truing the dope, the point is moot?

Lastly, anybody know what “ranging point” is on a reticle? Its a data point being asked by the app Im using.

[Thoughts]

Well, that's a bit messy. I think that the Strelok Pro program I use has a feature such that it uses multiple BCs for a single bullet in different speed regions. Maybe that concept has something to do with your quandary. I could be far off, though. Hopefully, someone will be able to provide some pointers to information. I would guess that G7 would be more accurate over the full range if the G7 estimate is any good. At this point, who knows.

If you are using dope, then you should be okay. My experiences with the calculators have been better some days than others, but, to be fair, there's a lot of missing input data that they need to estimate. You have a chronometer and a rangefinder, though. Sigh!

I haven't heard of a "ranging point", so I can't help you there.

[smoothy8500]

I used to use the manufacturers B.C. but now, I have access for different B.C. data.

I guess if I’m truing the dope, the point is moot?

I use Strelok Pro's internal library and the truing feature at 800yds by adjusting velocity.

Considering there are so many variables that can affect the accuracy of the calculator's solution "try dope" besides temp/humidity/barometer, the truing feature is working well for me.

[Fjold]

Since BC changes with velocity, air density, elevation, humidity, gravitational constant and probably phase of the moon there is no correct answer. I tend to use the G7 myself but there is no correct "one" number.

If you use an electronic target that measures velocity at the target and you measure velocity at the muzzle at the same time, it will give you the BC of your bullet for that one shot but that's the only way.

[chromatica]

You must have misquoted the Litz number. I have the Litz AB Mobile app with ballistics library. The BCs for the 75 grain BTHP (.224) are
G1 .354
G7 .181

Use either of these numbers and you will be fine.

[theLBC]

guy on another forum ran into this and based on his testing, found this to be correct

Hornady G7 - 0.326

his AB gave him the other number for G7 (as does my kilo), which is not correct based on his results.