calculating bc of a custom bullet?

[toolsofthetrade]

We are working with some custom bullet ideas, what is the easiest way to calculate a given bullets bc?

 

[BergerFan222]

Best to measure BCs. There are several methods. Try a google search for

how to measure ballistic coefficient of a bullet

 

[Browninglover1]

If you're designing them in a CAD program I imagine there's a way to do a fluid simulation that will help you determine BC. Another idea would be to get an accurate muzzle velocity using a Magnetospeed and adjust the BC in your ballistics program until it matches up to your real world drop (assuming you have any correction factors for your scope's turrets that need to be added).

 

[BergerFan222]

If you're designing them in a CAD program I imagine there's a way to do a fluid simulation that will help you determine BC. Another idea would be to get an accurate muzzle velocity using a Magnetospeed and adjust the BC in your ballistics program until it matches up to your real world drop (assuming you have any correction factors for your scope's turrets that need to be added).

Manufacturers should not be using BC numbers inferred from drop. There are simply much more reliable methods to obtain accurate BCs.

 

[Browninglover1]

Manufacturers should not be using BC numbers inferred from drop. There are simply much more reliable methods to obtain accurate BCs.

He didn't say he was a bullet manufacturer he just stated they were working with some custom bullet ideas. Besides, most of the manufacturers BC's aren't accurate enough to trust without tweaking, so BC's should be taken with a grain of salt. Berger and Sierra seem to do a better job than most but even they require tweaking in many rifles to get your programs to give accurate drop predictions.