Thread: Actual drops - speed calc

This past weekend I took the Savage 7mm08 up to Hamilton and shot at known distances at the end of each stage of a FTR compo. I was hoping to be able to work out the muzzle velocity from these actual drops, but I am still none the wiser.

When I zeroed at 100yds, the baro was 29.50 inHg, and temp was 55.7 F

I've used humidity of 50% for all calcs.

Rifle details:
7mm08, 1:9.5, 22 inch
Nosler BT 120gr, using Litz G7 published BC (0.185)
Sight Height 1.75 inch

Results I got:

300 yds
Baro: 30.46
Temp: 86.2
Drop: 4.25 MOA

500 yds
Baro: 30.43
Temp: 82.9
Drop: 9.25 MOA

600 yds
Baro: 30.40
Temp: 74.9
Drop: 12.25 MOA

All these are giving me pretty different MV. Maybe one of the clever monkeys on here can tell me what I am doing wrong...