Long Range Hunting Online Magazine


Go Back   Long Range Hunting Online Magazine > Rifles, Reloading, Optics, Equipment > Rifles, Bullets, Barrels and Ballistics


Reply

BC Article- Link

 
LinkBack Thread Tools Display Modes
  #1  
Old 02-03-2010, 11:49 PM
Gold Member
 
Join Date: Mar 2006
Posts: 845
BC Article- Link

The report I was quoting in my previous" BC/Drop" thread is from the November 2009 issue of GUNS magazine from an article named
"Ballistic Coefficient"
Here's a link -go to page 16
http://www.gunsmagazine.com/digital/GN1109.htm?page=16

Last edited by RockZ; 02-03-2010 at 11:52 PM.
Reply With Quote
  #2  
Old 02-04-2010, 02:34 AM
Platinum Member
 
Join Date: Feb 2009
Posts: 3,538
Re: BC Article- Link

Good read, thanks for posting.
Reply With Quote
  #3  
Old 02-04-2010, 04:52 AM
Platinum Member
 
Join Date: Dec 2001
Location: Mukilteo, WA
Posts: 1,091
Re: BC Article- Link

This is a good example why I don't read many gun magazines anymore. Most gunwriters, especially those in hunting magazines, are very non-technical people who simply don't have much understanding of ballistics and other technical subjects. JB has vast experience and knowledge on general hunting subjects, but ballistics, LR shooting and hunting, etc...sometimes I wish people would stick to writing about what they know.
Reply With Quote
  #4  
Old 02-04-2010, 05:25 AM
Platinum Member
 
Join Date: Feb 2009
Posts: 3,538
Re: BC Article- Link

Jon A, sounds like you may be upset with JB's article. Just curious if you are, what was it in the article that he said about ballistics, LR shooting and hunting, that makes you wish he'd write about what he knows?
Reply With Quote
  #5  
Old 02-04-2010, 07:08 AM
Platinum Member
 
Join Date: Dec 2001
Location: Mukilteo, WA
Posts: 1,091
Re: BC Article- Link

I'm not upset in the slightest. Just pointing out the obvious. If you'd like specifics from that article:

1) He gives the impression BC's are only valid under standard sea level conditions. Of course every ballistics program in existence will compensate for your actual environmental conditions so a sea level corrected BC is what you want. Using that method you can get accurate results anywhere you may happen to be on the planet. His mention of it gave the opposite impression.

2) The idea his crude drop measurements at 400 yds would be accurate enough to make comments on how long the bullet is yawing after the shot...quite laughable. The last time I saw him making ballistics comments based upon drops at 400 yds it turned out his group sizes were 9". Yes, 9". Hopefully this rifle shoots a bit better than that, but you get the point.

3) The overall impression the reader is left with is that BC's are not all that accurate and that they, along with ballistics software cannot be relied upon to accurately predict trajectory even out to only 400 yds. This is simply false. If he said 2000 yds, he could make a better case as that can get pretty darn difficult. But at only 400 yds if his results don't match predictions given accurate inputs it's due to flaws in his testing methods. But the article implies we should throw out all known exterior ballistic science because he got some phunky results once. I think this does a disservice to the readers.

And to give you another idea of where he's coming from, he has said elsewhere no scope used to hunt big game should have any sort of exposed turrets or parallax adjustment. If he doesn't need or want them for the type of hunting he does, that's fine. But it illustrates he isn't exactly a long range shooting/hunting enthusiast, much less authority.

Anyway, you asked so there you go. On subjects such as African hunting, tracking, other close range techniques, bullet terminal performance, etc, he is a wealth of information.
Reply With Quote
  #6  
Old 02-04-2010, 08:04 AM
Platinum Member
 
Join Date: Feb 2009
Posts: 3,538
Re: BC Article- Link

Quote:
Originally Posted by Jon A View Post
I'm not upset in the slightest. Just pointing out the obvious. If you'd like specifics from that article:

1) He gives the impression BC's are only valid under standard sea level conditions. Of course every ballistics program in existence will compensate for your actual environmental conditions so a sea level corrected BC is what you want. Using that method you can get accurate results anywhere you may happen to be on the planet. His mention of it gave the opposite impression.

Jon A, thanks for responding. I got a different impression cause actually, he wrote "vary any of those conditions and BC varies as well. Elevation has the biggest effect.

2) The idea his crude drop measurements at 400 yds would be accurate enough to make comments on how long the bullet is yawing after the shot...quite laughable. The last time I saw him making ballistics comments based upon drops at 400 yds it turned out his group sizes were 9". Yes, 9". Hopefully this rifle shoots a bit better than that, but you get the point.

I don't see where he said how long the bullet was yawing. He wrote "Barrel/bullet/crown combination results in a much shorter period of yaw something apparently impossible to predict. When it does happen however the bullet will shoot alot flatter than in any computer model

3) The overall impression the reader is left with is that BC's are not all that accurate and that they, along with ballistics software cannot be relied upon to accurately predict trajectory even out to only 400 yds. This is simply false. If he said 2000 yds, he could make a better case as that can get pretty darn difficult. But at only 400 yds if his results don't match predictions given accurate inputs it's due to flaws in his testing methods. But the article implies we should throw out all known exterior ballistic science because he got some phunky results once. I think this does a disservice to the readers.

I respect your impression and what you thought was implied. I got a different impression as I didn't read that BC's are not all that accurate and that they, along with ballistics software cannot be relied upon to accurately predict trajectory or we should throw out all known exterior ballistic science.

And to give you another idea of where he's coming from, he has said elsewhere no scope used to hunt big game should have any sort of exposed turrets or parallax adjustment. If he doesn't need or want them for the type of hunting he does, that's fine. But it illustrates he isn't exactly a long range shooting/hunting enthusiast, much less authority.

Can you provide the article/writeup on no scope used to hunt big game should have any sort of exposed turrets or parallax adjustment. Let me know.

Anyway, you asked so there you go. On subjects such as African hunting, tracking, other close range techniques, bullet terminal performance, etc, he is a wealth of information.
Again, thanks for resonding. It's good to get others opinions.
Reply With Quote
  #7  
Old 02-04-2010, 10:30 AM
Platinum Member
 
Join Date: Jan 2007
Location: MS
Posts: 1,652
Re: BC Article- Link

I like the article, thought it was a good non-technical read. But 400 yards is not gonna tell you shinola about the BC of a bullet. Exbal does not like his numbers for his junk science.

I do like the fact that the writer recognizes that BC is not a number you just plug into your ballistics program and go hunting. You have to shoot the damn things. Pus you have to shoot them at ranges further than you would shoot an animal. I have seen all kinds of strange stuff happening to BCs at longer ranges 1400+. Most of it can be compensated for by using multiple BCs or different form factors, but very rarely do the numbers give you your drops perfectly.

One way I have learned to mitigate slight errors in BC is to sight my rifles in at longer ranges. For instance, I usually sight my rifles in at 787 yards. If exbal proclaims that I need 12MOA for 787 yards I loosen the screws turn my dial to 12 and tighten them down. I then dial back to zero and should be zeroed in at 100 yards. Sometimes I end up 1/4 MOA +or- at 100 but find that it sort of slits the difference in any errors so that errors are masked at ranges past my 787 sight in distance.
__________________
I admit that I know just enough to be dangerous.....but dangerous at ever extending distances.
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes


Similar Threads for: BC Article- Link
Thread Thread Starter Forum Replies Last Post
Link to Long Range Bowhunting article Len Backus Bowhunting 1 06-21-2011 03:27 PM
Broken link bwaites Website & Forum Support 4 01-14-2008 07:29 AM
PLEASE take a look at this link and let me know what you think skip AI Equipment Discussions 10 10-05-2005 09:05 AM
Wildcat bullet link? rost495 Reloading 6 08-18-2005 06:56 PM

Current Poll
Where in the US do you live?
West of the Mississippi River - 60.67%
881 Votes
East of the Mississippi River - 37.05%
538 Votes
On the Mississippi River on a houseboat - 2.27%
33 Votes
Total Votes: 1,452
You may not vote on this poll.

All times are GMT -5. The time now is 12:49 AM.


Powered by vBulletin ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Management Powered by vBadvanced CMPS
All content ©2010-2014 Long Range Hunting, LLC