How to calculate BC

BC for dummies version.... Velocity change over distance... 2 chonys or one (shot over 2x in as much the same conditions as possible). vs distance the chronys were apart and some math I don't know 

I've never used this calculator but it shows the data inputs, it will do the math...

http://www.jbmballistics.com/cgi-bin/jbmbcv-5.1.cgi

http://www.jbmballistics.com/cgi-bin/jbmbcv-5.1.cgi

I'd use a different one than that. Math only. No G - something? drag to screw it up. 

I'm going to calculate my slugs over a 5 yard and 100 yard chrony with a math calculation I have somewhere....

Spyde82,

here's a BC table for .22 I've assembled from a ton of different sources. To make the table they had to be from high quality brands, have at least mid or high BC, and had to be available in the US.

Here's the pdf:

View attachment 1568680785_3192735415d802b516f9f34.52218871_BC Table for .22cal. Table Only. 2019-09. V 139.pdf



The longer doc with explanations and all background info is here (including a BC table on page 2 that is just a little bit older, it's missing some newer pellets like the JSB Hades and the Crosman Domed 19 grain "Ultra Heavy"):

https://www.airgunnation.com/topic/bc-table-22cal-comprehensive-internet-wide-collection-of-ballistic-coeff-data/



@ LongShot,

I think the BC calculations with ChairGun are going to be a bit more accurate, as they use the GA drag model instead of the G1 model.



Have fun! I find BCs fascinating, as they are hugely important for long range shooting and windy days.

Matthias