true bullet coefficient

[mo]

I think I read somewhere that if you get muzzle velocity and then get your velocity from a 100 yd. you can get your true bullet coefficient. Is that correct? Does anyone know that formula?

 

[Topshot]

Not real practical. Too many errors on such a short distance.

You have a very short time of flight and the accuracy of your chronograph to think about that may be a few%.

If you are interested in such things, buy Bryan Litz book.

 

[britz]

I think I read somewhere that if you get muzzle velocity and then get your velocity from a 100 yd. you can get your true bullet coefficient. Is that correct? Does anyone know that formula?

You need to spread the two readings out over a longer distance. The farther apart the more accurate you will be in figuring your BC.

Here is a link to Jbm calcuations page that will help you.

http://www.jbmballistics.com/calculations/calculations.html

 

[jenr234]

Brian Litz's book is excellent,easy to understand and not too technical.

 

[mo]

thanks gentlemen.

 

[Michael Eichele]

2 chronies work fine for a good place to start. The only thing you cant get is a drag model but will give you a DANG good place to start. 3 different times this year with 3 different loads I used the double chrony method to come up with a BC and put first round hits in the X ring at 700 yards.

My chronies are 300 yards apart. As far as caluclations, it is best to use a ballistic calculator.

 

[MontanaRifleman]

You should also check this thread and article out.

http://www.longrangehunting.com/forums/f5/berger-bullets-move-g7-standard-bc-bryan-litz-44399/

Very, very informative.

-MR

 

[mo]

I ordered his book today...