Range Report Ballistic profile help

[ptaylortx]

I'm trying to gather my data to send off to Leupold for a cds turret on my vx3 4.5-14x40. It's on a recent 308 built for strictly light weight hunter. I worked up a super accurate load with 165 Sierra gamekings bthp muzzle velocity of 2638 average, .363 listed bc. I've entered all the data, including scope height,(1.64"), altitude(roughly sea level), temp ect. Two ballistic calculators give me a vertical correction of 5.3 moa @ 300 with a 100 zero. The actual come up is only 4.5 moa. Seems a little excessive variance. The strelok program is spot on with my other rifles shooting matchkings. Could the bc be that far off or am I missing something?

 

[wrhunter]

Several factors at play here. BC could be part of it. Environmentals?
Accuracy of chrono?
Accuracy of POI - are you shooting paper or steel at 300 and is the group tight enough to get solid vertical dope?

I would try to get more data points at distance to see if you can true the velocity a bit. 300/400/500. The more the better.

For a .8 moa difference something has to be quite a bit off.

Also make sure you don't have g1 and g7 BC mixed up.

 

[ptaylortx]

I tested velocity with two chronos, shot groups off a caldwell rock with rear bag, 4 shot groups measured just over 1" [MENTION=89035]300[/MENTION] on paper. BC is straight from sierra and I don't believe strelok uses g7. Going to test it at 500 on my next day off and see where I am in relation to the calculations.