<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: milo-2</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MinorDamage</div><div class="ubbcode-body">Litz. Try not to toss his numbers around here. There is a reason they are hidden in ballistics calculators...it's not free to get the info.
Josh </div></div>
WTF?
Please, let me hear the logic.
Miles </div></div>
The logic behind not showing the BC's in programs is related to copyright/IP. Plainly put, the experimentally determined BC's in my book comprise a great deal of the books value. If someone can buy a $10 app and have access to all those numbers, it could disincline many people from buying the book. I have an agreement with all the app developers who use my BC library. They're using it freely which enhances the accuracy/value of their apps. In exchange, they agree not to make the BC's visible which protects my IP and people are more encouraged to consider the book.
However, the point of having done all that work is to benefit shooters. I don't have a problem with guys sharing a few numbers relevant to a conversation; that's fine. I just don't want the whole list (or large parts of it) to be freely and easily available online.
On that note, I am making some bullet data available on my website as a sort of 'teaser' for the data contained in my book. You can see full data on a handful of bullets on my website:
Bullet Data
Regarding Lapua, good on them for stepping up and providing radar based G7 BC's for their bullets. For quite a while they had the radar data (Mach-CD data) available for download which was a tremendous resource. Problem was they were still listing G1 BC's that represented vastly different performance than what was reflected in the radar data. I think it's been about a year ago now that they re-assessed all their BC's to be in better alignment with their radar data, and also provided the BC's referenced to the G7 standard. These radar based G7 BC's are, for the most part, very similar to what I've assessed.
The performance I measured for the 6.5mm 123 Scenar is:
G1 BC: .519
G7 BC: .265
(both averaged from 3000 to 1500 fps)
Lapua has this bullet at G1: .527 and G7: .263. Odd that one's + and one's -, but we're talking about 1.5% difference in the G1 and 0.8% difference for the G7. So Lapua and I are practically representing the same performance. I suspect the larger difference in the G1 comes from velocity dependence (we probably averaged over different speed bands). The G7 BC of .263/.265 is the number I would use.
An added note, the 6.5mm 139 gr Scenars that I tested had a slightly larger than average meplat/tips (.076" diameter, whereas the 108 and 123's I tested had meplat's of .064 and .061). Point is that my assessed performance for the 139 may be a little lower than average if the average 139's have smaller meplat's.
Take care,
-Bryan
