Here's the lowdown on my latest field test with the Hornady 162gr A-MAX. Comparison of Patagonia Ballistics' LoadBase 3.0 predicted 985 yard velocity (using Bryan Litz's G7 BC = 0.307) versus measured 985 yard velocity.
Cartridge is .280 RCBS Improved with 28" 1:9" twist Brux barrel. I captured two (2) 985 yd velocities over my chronographs; 1) 1580.9 fps, and 2) 1582 fps. This yields a two-shot chronographed 985 yd average velocity
= 1581.4 fps
Environmental Conditions = 29.43 in/Hg, 47F, 48%RH
60.4 degrees North Latitude
50 degree direction-of-fire Azimuth
Muzzle Velocity = 2948 fps
Stability Factor = 1.64 with the 162 A-Max in my 1:9 twist Brux.
Default Drag Coefficient = 0.500
LoadBase 3.0 (with coriolis and spin drift features activated) predicted 985 yd velocity = 1590.2 fps
versus the chronographed 985 yd velocity = 1581.4 fps
. A difference of 8.8 fps
@ 985 yds, for another very good correlation between predicted velocity (using the G7 BC and the default LoadBase 3.0 Drag Coefficient of 0.500) versus measured velocity.
I'll tweak the G7 BC in my LoadBase 3.0 saved "Track" from 0.307 to 0.305 in order to obtain a better predicted match to my measured 985 yd velocity. Gus would probably tell me to tweak the Drag Coefficient, but this is such a small modification to Bryan's G7 BC that I think it matters little which is tweaked.
The 1/2" AR500 protective plate prevented bullet destruction to 4 skyscreens today. The AR500 steel is tough stuff. I can't see or feel any surface deformation where the bullet impacted. Nothing more than a surface splash on the white paint.
Photo of my chronograph setup showing the 4 skyscreens that survived the "near-death" experience. I don't install the orange and white skyscreen shades at distances past 300 yds.