6.5 Lapua 139 Scenar BC?

[XTREM HTR16]

I’ve read posts on the 139 Scenar claiming BC of anywhere from .560 to .615. What is the standard used by Hide members?

 

[Pvt.Donut]

I think I was using .564 with good results. This was in Strelok. Not the slipperiest bullets but they were consistent.

 

[jarhead1077]

I shoot .260 Rem and use the Lapua Scenar 139. Mr Litz had listed G7 at 0.301. My Model 12 LRP Savage 26 inch barrel found actual G7 BC of 0.291. I shoot out to 800 yards and at 600 regularly with the 0.291 G7 and StrelokPro is on the money at 600 yards and average 2815 fps MV. Using standard conversion for velocity equals 0.583 for G1 equivalent.

JBM - Calculations - Drag Function Conversion

www.jbmballistics.com

Drag Function Conversion Input Data Ballistic Coefficient: 0.291 G7 Caliber: 0.260 in Bullet Weight: 139.0 gr Velocity: 2815.0 New Drag Function: G1 Output Data Speed of Sound: 1116.4 ft/s Mach Number: 2.521 CD of Standard G7 Bullet: 0.269 CD of Standard G1 Bullet: 0.538 Form Factor of G7 Bullet: 1.009 Form Factor of G1 Bullet: 0.504 New Ballistic Coefficient: 0.583 G1 Sectional Density: 0.294 lb/in²

14-Apr-19 23:28, JBM/jbmgf-5.1.cg