.222

[mtbullet1]

just a heads up on NEW B/C figures. pulled older .222 out to recheck loads from the past
using sierra #1330 50 gr, with H322, check velocity and did drop chart and ,wow was it off!
so checked new B/C from Sierra , and it says .222, the old figures i used said .192, and that
made the drop chart come in line with field testing. So, if your old like me, throw old data out and get new !

 

[RegionRat]

In general, book values for ballistic coefficients are only used for estimates to get started.
Anything serious requires actual testing in context since barrels can affect bullet drag and in turn the BC.
My comment applies to climate and to windage, not just elevation/drop, so testing wind drift ahead of anything important and in as many different conditions is my advice.

 

[mtbullet1]

In general, book values for ballistic coefficients are only used for estimates to get started.
Anything serious requires actual testing in context since barrels can affect bullet drag and in turn the BC.
My comment applies to climate and to windage, not just elevation/drop, so testing wind drift ahead of anything important and in as many different conditions is my advice.

I know , testing was how I discovered new b/c, my point was "check for new info"