close
Long Range Hunting Online Magazine


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

Rifles, Bullets, Barrels & Ballistics Applied Ballistics

Reply

Lets Talk Stepped BC's

LinkBack Thread Tools Display Modes
  #15  
Unread 08-09-2011, 04:58 PM
Platinum Member
 
Join Date: Feb 2007
Location: Townsend, Montana.
Posts: 8,548
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  
    Unread 08-09-2011, 05:22 PM
    Silver Member
     
    Join Date: Sep 2010
    Location: New Zealand
    Posts: 379
    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  
    Unread 08-09-2011, 05:26 PM
    Platinum Member
     
    Join Date: Feb 2007
    Location: Townsend, Montana.
    Posts: 8,548
    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  
    Unread 08-09-2011, 06:59 PM
    Silver Member
     
    Join Date: Jan 2010
    Location: AZ
    Posts: 305
    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  
    Unread 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  
    Unread 08-09-2011, 08:27 PM
    Platinum Member
     
    Join Date: Jun 2001
    Location: Potomac River
    Posts: 5,071
    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  
    Unread 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 & 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 & Ballistics 16 06-21-2004 01:53 PM


    All times are GMT -5. The time now is 01:50 AM.


    Powered by vBulletin ©2000 - 2017, Jelsoft Enterprises Ltd.
    Content Management Powered by vBadvanced CMPS
    All content ©2010-2015 Long Range Hunting, LLC