True BC of Lapua 6.5mm 139gr

[Thor2j]

What is the real BC of the Lapua 139gr Scenar. The Lapua website says .578 while half of the dealers advertise as .615??

 

[ksthomas]

Re: True BC of Lapua 6.5mm 139gr

Thor2j,

The .615 figure was an older number, which may have been determined by time of flight testing. That has since been revised to .578 (G1), or .290 (G7), based on Doppler radar firings. Given the two methods involved, go with the current figures (.578 or .290, respectively) as being the most accurate. We're in the process of refiring some of the data as we add new bullets to the line, and the Doppler radar data is by far the most accurate method of deriving BCs. Unfortunately, it's also very expensive, and time consuming.

Hope that helps.

 

[Lowlight]

Re: True BC of Lapua 6.5mm 139gr

Kevin

Thanks for the info, I use .585 but will revise my numbers to .578 as I tend to shoot the 139 more than any other 6.5.

Cheers,

 

[me124704]

Re: True BC of Lapua 6.5mm 139gr

Bryan Litz's book shows a G1 of .557 and a G7 of .285.