G1 vs G7: VERY Different Numbers for .308 Going Transonic

[vliberatore]

So I'm getting ready to test some loads for a match next month and I'm getting VERY different numbers for 175 SMKs going transonic.

G1 is saying ~1200yards
G7 is saying ~2200 yards

MV is 2720fps
DA is 1155ft
I have bullet length at 1.245"

BC is .496 (from Sierra's website)

As I understand it, G7 is gernerally more accurate than the G1 model but this doesn't seem right. Any ideas on what (if anything) I'm doing wrong? Surely a .308 isn't going to stay stable that long...

[phish]

G1 vs G7: VERY Different Numbers for .308 Going Transonic

I think you're plugging in the G1 value with your app set for a G7 value.

[vliberatore]

I think you're plugging in the G1 value with your app set for a G7 value.

That was it. Thanks.

If anyone else is wondering, I found that the 175 SMKs have a G7 BC of .243

[bsumoba]

Try Strelok Pro for your phone...such a good value for the money

[Knife Edge]

That was it. Thanks.

If anyone else is wondering, I found that the 175 SMKs have a G7 BC of .243

Confirmed.

[russ69]

The real calculations are very complicated and BC changes with speed, so it's constantly changing. You can confirm being sonic by asking the target puller at 1000 yards if the bullet is cracking loud when it passes.