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BC (ballistic coefficients) don't bet on it

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cruft View Drop Down
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Joined: November/20/2005
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Post Options Post Options   Thanks (0) Thanks(0)   Quote cruft Quote  Post ReplyReply Direct Link To This Post Topic: BC (ballistic coefficients) don't bet on it
    Posted: February/08/2012 at 13:22
The latest issue of Varmint Hunters magazine has  an article comparing BC of bullet manufactures against real world testing.  This is an almost impossible task when you think about it.  Just think of the variables.  OK now sit down and take a deep breath.  So now that you head is spinning the author did, in a small universe, make a case.  Results; Sierra and Hornady good, Nosler yuck.  You just can let the marketers have any say so.  But more than that, and the reason this is here under "varmint scopes, is that MPBR is not viable for small targets (vial areas) after 250 yes and less.  This is not the case for large with a vital area of 10".  The long distance of 500 yds the BDC reticle just runs out of usefulness.  I don't know the reality of the Horus reticle, being that a small compute at the site and need of SFP are required.  Hopefully one of you will advise.  AnywayLike the Book of James ZI started on one topic and wandered into another.  Moral Don't believe manufacturer's numbers, but who didn't know that.  Oh and we still need clicks.
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Bitterroot Bulls View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bitterroot Bulls Quote  Post ReplyReply Direct Link To This Post Posted: February/08/2012 at 13:44
The specific rifling grooves on the prjectile from specific rifles also affect BC.  I find my own BCs by using a ballistic calculator and shooting through chronographs at 10 feet and 200 yards.
 
I am usually just under Nosler's published BCs and just over Barnes' BCs.
 
Berger's are very close.
-Matt
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Dale Clifford View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dale Clifford Quote  Post ReplyReply Direct Link To This Post Posted: February/08/2012 at 16:27
JBM internet program gives good bc if you use the Litz option, which will also give you spin drift. Most programs give calculated bc from some type of on going correction to the g1 as it decreases in velocity. Snipershide has an ongoing discussion as to bc and point mass changes and their effects in the marksmanship section. Patagonia does not believe these systems are accurate and uses drag functions based on velocities at different distances, then uses curve fitting techniques to find the actual drops. What does this all mean to the ave. shooter. Not much if they aren't chronographing and using sd and spread.
I love little league baseball-- it keeps the kids out of the house
Yogi Bera

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jonoMT View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jonoMT Quote  Post ReplyReply Direct Link To This Post Posted: February/08/2012 at 21:07
Litz details in his book, Applied Ballistics for Longrange Shooting, the tests they did on a variety of popular bullets. I only use one Nosler bullet, which is the .308 165 gr. Accubond, and it did have a lower BC - verified by my own shooting. I still find it to be a great bullet for hunting elk, deer and antelope, but wish Nosler's figure had just been more accurate in the first place.
Reaction time is a factor...
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