BC may not be BS

[52Bore]

In a previous post, Dead Center BC - it seems they are Way off the mark.
I also found an article that Hornady SST BC were mentioned to be off - I could not help but wonder?
Looking at BH209 data, I noticed both 250 & 300 SST were tested - I can only assume BH209 MV is correct.

Thinking one way someone could test the BC of a bullet to compare to the manufacture listed BC is to actually test with a Chrongraph (MV) at different distances and see where the bullets impact. i.e. if your elevation is 0 at 100, drop x" at 200, drop xx" at 300, etc..
So, using Hornady's Ballistic Calculator I put in both Hornady's BC and BH209 MV to create the result.
250gr SST, BC-0.21, MV-2119


BC-0.184, then only changing MV until the drop = actual Hornady results (very close).


The difference in Chronograph measurement could be as little as 3% (70fps) to change the BC 14%.

 

[52Bore]

Here is the same test with the 300 SST

300gr SST, BC-0.25, MV-2050


BC-0.226, changing MV to match drop


Again, a Chronograph difference of 2.4% (50fps) to change the BC of 10% (0.25 to 0.226)

Seems a little variance in MV has a much larger effect to BC.

 

[52Bore]

I was looking out to 300, as the drop is very close. 4 & 500 are listed, but doubtful actual accurate field testing could be done at those ranges.