Have you or anyone you personally know, verified that bc?
Yeah, I zeroed and ran a JBM trajectory chart in close intervals based on 600 yard shots before I took that rifle to Montana. Thanks to my friend’s Labradar, we trapped velocity at the muzzle and at the ShotMarker (610 yds).
With velocities measured at two known distances significantly far apart from each other, I used the method I have used in the past to calculate drop.
Using the manufacturer’s weight (not that it matters) BC (matters) and MV, as a starting point at my elevation, I run a trajectory and see how closely it resembles the Target velocity reported.
In this case, the match up was spot on. I shot into the prevalent headwind that day of about 10-15 FPS (typical match, possibly more as I shot quickly after a match at the patience of competitors) ShotMarker reported 2,383 average of 4 shots at 600 (610) although the Labrador picked up only three out of four shots. The Labradar showed an average of 2,986 at the muzzle.
If you run those numbers with the headwind factored in, the G1 BC will have to hover at 1.0+ to make the MV and 600 yard numbers match what was reported. That’s the same figure Lehigh claims.
That BC claimed by Lehigh comports with my range experience shooting fast, low drag 7mm’s with BC’s in the .7’s, plus. While I have gotten, for example, the very high BC 183 SMK to cross at over 2,400 FPS at the 600 target, it needed
substantially higher MV to do so.
