.22 RimFire Ballistic Coefficients

[gitano]

j0e_bl0ggs sent me the following that he got off of the RimFireCentral forum some time back. It is no longer available at RFC, and we don't know why. Regardless, I am posting it here in the Reference Library for what should be obvious reasons, and I will also put it in "Reloading" but not "stuck" there. I'm going to 'lock' this thread here in the Reference Library, so you can make comments in the "Reloading" thread.

Neither j0e_bloggs nor I vouch for the values in this table, but the few that I have cross-checked at other sources - like manufacturer's sites - have checked out. Nonetheless, use these data with appropriate consideration of their origins.

I had to take screenshot 'pictures' of the spreadsheet in order to present the data here.








We also found this table with explanation through the Sierra site. Note it's comparison to the above values.


I am going to generate some graphs using the above data. I'll post them here when I'm finished.

Paul

[gitano]

Here's the graph of the Sierra data:


So if you want to predict the ballistic coefficient (BC) of YOUR .22 caliber ammo from YOUR rifle:
1) Measure the muzzle velocity (or get it from the manufacturer's box or site),
2) Find the range into which that MV fits (for example, is it less than 905 f/s, use the upper model; if more than 1047 f/s, use the lower model; if between 905 and 1047 f/s, use the middle model),
3) put your bullet's weight in place of the "X" value in the model (equation).

When you solve the equation, the value you get will be the estimate of the BC for your ammo from your firearm.

Paul