Saw this thread, and it was informative..bc changes as a factor of velocity...
Some projectiles refrence it, others do not..
It was a decent read on page 2..
http://thefiringline.com/forums/show...=555006&page=2
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Saw this thread, and it was informative..bc changes as a factor of velocity...
Some projectiles refrence it, others do not..
It was a decent read on page 2..
http://thefiringline.com/forums/show...=555006&page=2
Some bullet makers offer BC's based off velocity.Quote:
Originally Posted by mapper
Yes, they shoot through two chronographs,one at the muzzle and one downrange.Quote:
Originally Posted by Airgator0470
Crunch the numbers then spit out an average.
I've read somewhere that the only true way to get accurate bc numbers is by doppler radar.
So we need to shoot at the giant golf ball at the airport? :dunno:
I believe the army has Doppler at Aberdeen testing grounds.
So does that TV station just North of I-10 on Thomasville road. :chinscratch:
ROADTRIP!!!
I have seen diffeent bc' based on velocity, seen where some people take a average of the bc then plug that in the drop charts.
Seen others only give 1 bc, and use muzzle velocity to run charts with..
Seen others use g7 data...
It is still an approximation..
It really helps if you have the bc to velocity numbers for the bullet you are using.Quote:
Originally Posted by mapper
Tell me what bullet you want to use and I will see if I have the numbers.
Here is an example.
Fps BCg1 BCg7
1500. 0.565. 0.314
2000. 0.629. 0.317
2500. 0.651. 0.327
3000. 0.678. 0.332
Those numbers are for Hornady .338 250gr BTHP Match.
And of course you probably already know this but I'll say it anyway.
G1 looks like a pistol bullet,flat base and rounded ogive.
G7 has a boat tail and a pointy ogive.
So G7 data reflects most modern bullet designs.