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Range Report bc of 190 smk?? im getting different answers from

cruze5

Gunny Sergeant
Full Member
Minuteman
Nov 11, 2006
723
107
Kentucky
two different programs.

one its listed as .533

another .524

this is loaded HSM ammo btw.
 
Re: bc of 190 smk?? im getting different answers from

The 190gr SMK has multiple BC's depending on the speed that it is traveling.

If you look at Serria's site, it breaks out the BC vs velocity.

I believe you need to use the G7 drag model to calculate trajectory.
 
Re: bc of 190 smk?? im getting different answers from

.308 dia. 190 gr. HPBT MatchKing

.533 @ 2100 fps and above
.525 between 2100 and 1600 fps
.515 @ 1600 fps and below
 
Re: bc of 190 smk?? im getting different answers from

I've measured an average BC of 0.527 for this bullet (about 0.5% higher than Sirras average value).

GB is right though, the G1 BC is highly affected by velocity and the G7 BC would be better to use to predict long range trajectories for this bullet.

I measured the G7 BC of this bullet to be 0.270, and it only varies by 0.006 from 3000 fps to 1500 fps (the G1 BC varies by .071).

Make sure your program can accept G7 BC's and that you have it set to use a G7. Otherwise, you will get a non-physical trajectory and your computer will melt.

Take care,
-Bryan
 
Re: bc of 190 smk?? im getting different answers from

Zombie thread revival, but hey this is useful intel. Thanks for all your work and sharing it with us Bryan, even two years later I stumble across it and it's still just as useful.