Long Range Hunting Online Magazine


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


Reply

Lets Talk Stepped BC's

 
LinkBack Thread Tools Display Modes
  #15  
Old 08-09-2011, 04:58 PM
Platinum Member
 
Join Date: Feb 2007
Location: Townsend, Montana.
Posts: 7,759
Re: Lets Talk Stepped BC's

Quote:
Originally Posted by Topshot View Post
BROZ,

Interesting ideas. How do you determine the correction for your second curve?.

Well that is why I started this thread. The only way I know is to shoot the actual distances at least every 100 yards and document drops. Then use this data to "Tune" BC and Velocity to match up.

Jeff
__________________
Reply With Quote
  #16  
Old 08-09-2011, 05:22 PM
Silver Member
 
Join Date: Sep 2010
Location: New Zealand
Posts: 311
Re: Lets Talk Stepped BC's

[QUOTE=Broz;534874]Well that is why I started this thread. The only way I know is to shoot the actual distances at least every 100 yards and document drops. Then use this data to "Tune" BC and Velocity to match up.

Jeff[/QUOTET

The only down side I can see to that idea are very slight up and down winds to the target at extreme range, sometimes they are very hard to detect and can make you unsure of what is really happening with your true scope wind up.
Reply With Quote
  #17  
Old 08-09-2011, 05:26 PM
Platinum Member
 
Join Date: Feb 2007
Location: Townsend, Montana.
Posts: 7,759
Re: Lets Talk Stepped BC's

[QUOTE=Rocky Mountain;534883]
Quote:
Originally Posted by Broz View Post
Well that is why I started this thread. The only way I know is to shoot the actual distances at least every 100 yards and document drops. Then use this data to "Tune" BC and Velocity to match up.

Jeff[/QUOTET

The only down side I can see to that idea are very slight up and down winds to the target at extreme range, sometimes they are very hard to detect and can make you unsure of what is really happening with your true scope wind up.
Yes this is a fact. This is why you need to make the same shot over and over on different days while compiling data. I find early am best.

Jeff
__________________
Reply With Quote
  #18  
Old 08-09-2011, 06:59 PM
Silver Member
 
Join Date: Jan 2010
Location: AZ
Posts: 231
Re: Lets Talk Stepped BC's

Broz, you are in a position to use stepped BCs. You have a lot of data compiled, especially with the time in Idaho. I thought the 2 bullet option in shooter is pretty clever. You have the info to go back in and "tune" you BC to find a good fit. I'm pretty interested in the new program Bryan spoke of. The adjustable base sounds neat too. I need to stop reading your posts regarding rangefinders. The last thing my bank account needs is a PLRF.
Reply With Quote
  #19  
Old 08-09-2011, 07:56 PM
Silver Member
 
Join Date: Jul 2010
Posts: 420
Re: Lets Talk Stepped BC's

I'm not an expert but I do shoot milk jugs at 1800yd. (only 1 out of 17 average ). There are only 2 BC's: supersonic and subsonic. All of the stepdowns are because the bullet does not match the standard profile worth a hill of beans. I feel that for ELR you need do figure out what your actual supersonic and subsonic BC is (out of your barrel). It doesn't matter what the bullet is rated at because they all swage up differentently in different barrels and at ELR small differences are tremendously large. Place a heavy metal plate in front of your second chronograph, find the distance that equals the last of supersonic velocity and then go out another 200yds. for subsonic. Now there is no more step up, down, sideways or inside-out BC popcorn balls. BC is a marketing substitute for shinola.
Reply With Quote
  #20  
Old 08-09-2011, 08:27 PM
Platinum Member
 
Join Date: Jun 2001
Location: Potomac River
Posts: 5,057
Re: Lets Talk Stepped BC's

For a couple of reason that I hope I have corrected, I am always low at ELR, usually about 1-2 MOA. I have reworked all of my charts and have both the G1 and G7 charts agreeing within 0.3 MOA at 2500 yards so we will see in a month and a few days whether that helps. I would say that between Bryan's book and his ballistic program, JBM and Exbal that things are looking much like the data that I was recording last year so hopefully I have my stars and ducks all lined up now. The thing is that at 2500 yards even 0.3 MOA is a big chunk of real estate.
__________________
The Smokin Fur Rifle Club
Reply With Quote
  #21  
Old 08-09-2011, 10:02 PM
Platinum Member
 
Join Date: Jan 2007
Location: MS
Posts: 1,652
Re: Lets Talk Stepped BC's

Maybe you can get Bryan to run you a you one of these. I could not get it to copy correctly but it is quoted from a thread here.

I ran a custom drag profile for the 7mm 200 grain ULD, see below:


Vel G1 BC G7 BC
4000 0.830 0.349
3900 0.819 0.351
3800 0.809 0.353
3700 0.799 0.355


I have resorted to stepped G1 BCs in a couple instances, it is a pain. About the only way I know to do it is get your actual drops and reverse engineer.
Other than that I am not saying anything in this thread.
__________________
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: Lets Talk Stepped BC's
Thread Thread Starter Forum Replies Last Post
Lets Talk Primers Firecat Long Range Hunting & Shooting 32 12-16-2010 11:21 PM
Lets talk the SA and 338 bullets ICANHITHIMMAN Rifles, Bullets, Barrels and Ballistics 9 06-07-2010 09:54 PM
Lets talk .338 bullets angus-5024 Long Range Hunting & Shooting 43 01-14-2010 09:07 PM
Lets talk brands BrokenHorn The Basics, Starting Out 6 02-28-2006 04:57 AM
Lets talk best LR cartridge vs accuracy! Nighthawk Rifles, Bullets, Barrels and Ballistics 16 06-21-2004 01:53 PM

Current Poll
I currently have hunting preference points in the following states

All times are GMT -5. The time now is 12:53 PM.


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