it's not that different because Hornady and Litz both are using Doppler to measure the bullets.
They are what they are.
As to why you're not getting published BCs, is because they run those samples of a test barrel.
They are never the same rifle to rifle, which others above have explained.
This has more to do with YOUR barrel, YOUR velocity, and YOUR atmospherics. This can be summarized as MACH, which Hornady publishes.
Linked here:
https://www.hornady.com/support/ballistic-coefficient
And is as follows:
338 Cal 270 gr. ELD-X
Mach 2.5
0.757 G1
0.381 G7
Mach 2.0
0.745 G1
0.374 G7
Mach 1.75
0.739 G1
0.372 G7
Poor truing habits is another thing I've seen throw people off. Don't go adjusting BC to change your dope, within supersonic. Adjust BC around or after Transonic.
Or better yet, if you use AB, opt for a custom curve, they work better.
First, thank you for the link. I was not aware of that data. It seems to confirm that my adjusted BC of .345 is significantly low.
As to what you and MM and RockyMt have stated, I do not disagree with the information you all have stated. But it did not answer my question. It did answer how variables affect BC calculations and why that happens, but my questions is what BC are others using. Have you actually used the .338cal 270gr ELDx? If so, What data did you input for BC into your ballistic app?
I believe I have an equipment problem I am trying to troubleshoot. Maybe my Magnetospeed is no longer within specs, maybe my ballistic app sucks, or maybe others see SIMILAR, NOT EXACT data to my experience and I'm just fine. I'll look into the AB app and the custom curve, that sounds pretty cool, always happy to find a more accurate solution.
As to trueing habits, this is my process after zeroing with a chosen load. Maybe this is contributing?
1) input advertised G7 BC and 5-shot chrony avg velocity plus environmental from kestrel and gun details into app
2) shoot at 600, 800, and 1000 and record DOPE ( repeat this step at least 3 times over different days) in field conditions
3) adjust BC or speed, but not both, to get app to match real world data.
I commonly harvest game in the 800 and less range, hence the chosen ranges.
I read more than I type on his forum and I think the educational information can be awesome, but I think the previous responses jumped to education, when all I asked for was data. I have reviewed my DOPE again and realized my wind inputs were very close(within my shooting capabilities), it was only the elevation that needed adjustment. I am leaning towards chrony error.
