.391 is too high unless your running a sub 1 in 8 twist. Typically you want to use the mach 2 or 1.75 given BC as a start with the ELDs for any sort of range. For the 180 and a 1 in 8.75 that's 0.364 or 0.376. I use hornady 4DOF so I've always found it pretty close only needing minor tweaking.
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