Norma USA Match Ammunition 6.5 Creedmoor 130 Grain Golden Target Hybrid Hollow Point Boat Tail..G1 or G7?

[Nicholas711]

So I need some help! So Im trying to figure out why the Norma 6.5 130gr Golden Tgt Hybrid BT uses a G1 drag scale. I bought the AP book to get a better understanding of ballistics. At this point I have a million questions and Im only on chapter 2. Correct me if Im wrong but the Norma bullet mentioned should be using the G7 Scale. My question is why is it using a G1 instead of a G7 if its a new bullet. Also, in the AP library it only list the Norma Diamond, FMJBT and both are using G7 .264BC.

Thanks in advance.

 

[Kobyashi72]

G1 =.548 Norma published average

G7 =.288 Norma published average converted to a G7 average (G1 BC multiplied by .512)


G1 = .576 AB published average

G7= .295 AB published average


G1 has been used longer so it’s the default scale they publish most of the time. Most of the time people pick it out of convience

The G7 refrence projectile is more representative of the shape of modern bullets but neither of them is going to be an exact performance match to the bullet you’re shooting.


You can pick a G7 and compare the difference between the two published G7 BC’s to see which one lines up closer to your real word data and adjust from there. Your rifle might match closer to Norma’s published average or it might match closer to AB’s published average.

You can also compare the predictions between both G1 BCs and compare the predictions from both G7 BCs and see what lines up the closest to your real world data then make adjustments from there

I personally pick between two G7s just to have a consistent standard for myself if CDM is not available for a given bullet.

Your mileage may vary

 

[Nicholas711]

G1 =.548 Norma published average

G7 =.288 Norma published average converted to a G7 average (G1 BC multiplied by .512)


G1 = .576 AB published average

G7= .295 AB published average


G1 has been used longer so it’s the default scale they publish most of the time. Most of the time people pick it out of convience

The G7 refrence projectile is more representative of the shape of modern bullets but neither of them is going to be an exact performance match to the bullet you’re shooting.


You can pick a G7 and compare the difference between the two published G7 BC’s to see which one lines up closer to your real word data and adjust from there. Your rifle might match closer to Norma’s published average or it might match closer to AB’s published average.

Compare the predictions between both G1 BCs and compare the predictions from both G7 BCs and see what lines up the closest to your real world data then make adjustments from there

I personally pick between two G7s just to have a consistent standard for myself if CDM is not available for a given bullet.

Your mileage may vary

Thanks Brother!