close
Long Range Hunting Online Magazine


Go Back   Long Range Hunting Online Magazine > Rifles, Reloading, Optics, Equipment > Reloading

Reloading Berger Bullets

Reply

Jumping and Jamming Clarification

LinkBack Thread Tools Display Modes
  #1  
Unread 02-04-2011, 03:38 PM
Bronze Member
 
Join Date: Mar 2010
Location: San Antonio, Texas
Posts: 44
Jumping and Jamming Clarification

When we refer to jumping and jamming to the lands, are we referring to distance to the bearing surface to the lands?
Reply With Quote
  •   #2  
    Unread 02-04-2011, 03:55 PM
    Platinum Member
     
    Join Date: Aug 2003
    Location: NC, oceanfront
    Posts: 4,057
    Re: Jumping and Jamming Clarification

    No. It's distance w/resp to bullet nose contact point.
    This can vary a good amount between different bullet ogives and your leade angle.
    Reply With Quote

      #3  
    Unread 02-04-2011, 04:11 PM
    Platinum Member
     
    Join Date: Jan 2007
    Location: PA
    Posts: 1,284
    Re: Jumping and Jamming Clarification

    That is true, its the point where the fattest part of the bullet (called ogive) first touches the lands in the bore. Jump means the distance the bullet goes before hitting the bore, and jam means how far touching the bore the bullet is seated.

    Bearing surface: The length of the bullet jacket which actually is engraved as the bullet travels thru the bore.
    Reply With Quote
      #4  
    Unread 02-04-2011, 04:19 PM
    Bronze Member
     
    Join Date: Mar 2010
    Location: San Antonio, Texas
    Posts: 44
    Re: Jumping and Jamming Clarification

    So you can't really use a bullet comparator to measure this distance?
    The reason I ask is because I'm trying to get the 180 grain Ballistic Tips to shoot in my .308 Win. I so far haven't had any luck. I thought I might try using a bullet comparator and set it to the same distance as my 175 smk loads (which shoot great). I haven't had any luck so far with varying the powder load.
    Reply With Quote
      #5  
    Unread 02-04-2011, 04:38 PM
    Platinum Member
     
    Join Date: Aug 2003
    Location: NC, oceanfront
    Posts: 4,057
    Re: Jumping and Jamming Clarification

    Quote:
    Originally Posted by Gene View Post
    jam means how far touching the bore the bullet is seated
    If this were true you could not easily 'Jam' a tangent ogive with a common 1.5deg leade angle, as these ogives contact nearest the groove(secants contact nearest the bore).
    In otherwords, anyone would have to fully engrave a tangent ogive to call it jamed, and I have never heard of anyone doing this(it would take huge neck tension to engrave rifling all the way to bore point here).
    Seems like I'm misunderstanding something here...

    Ed, you could use a single comparator to compare them -if the ogives were the same type and radius. But SMKs won't likely match your ballistic tips.
    You really have to start over with new seating tests.
    Reply With Quote
      #6  
    Unread 02-04-2011, 04:42 PM
    Bronze Member
     
    Join Date: Mar 2010
    Location: San Antonio, Texas
    Posts: 44
    Re: Jumping and Jamming Clarification

    Thanks Mike, I appreciate your help
    Reply With Quote
    Reply

    Bookmarks

    Thread Tools
    Display Modes


    Similar Threads for: Jumping and Jamming Clarification
    Thread Thread Starter Forum Replies Last Post
    Trick to jumping bullets??? tim jurczak Reloading 8 07-20-2011 12:42 PM
    A Good Jumping Point dWeller Rifles, Bullets, Barrels & Ballistics 2 02-13-2008 09:48 PM
    Jamming into lands Okiecat Reloading 4 01-27-2007 06:15 PM
    SAKO 75 300 WHYBY MAG JAMMING ON SECOND SHOT topwhop Rifles, Bullets, Barrels & Ballistics 1 10-27-2006 03:10 PM
    cant get scope to stop jumping jjohnson Long Range Hunting & Shooting 7 08-14-2004 07:42 PM


    All times are GMT -5. The time now is 03:49 PM.


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