Long Range Hunting Online Magazine


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


Reply

collapsed cases in a 7mmRUM?????

 
LinkBack Thread Tools Display Modes
  #1  
Old 03-06-2004, 09:27 PM
Silver Member
 
Join Date: Sep 2002
Posts: 453
collapsed cases in a 7mmRUM?????

I have heard of this happening with this caliber,..and last night saw it for myself. The load was 94gr of retumbo behind a 162gr a-max in a sendero SF. The same load printed ~.5moa last weekend with a temperatire difference of no more than 10 degrees. Lst night on a hunt,..a buddy fired one more and the case came out with 2 collapse marks just under the body/shoulder junction 180 degrees apart. The barrel was completely clean and dried,..the chamber was dried, and the bullets are at the lands. Anyone have any idea what causes this in this caliber?
__________________
You try to get closer to the target,..and I keep trying to get further away.
Reply With Quote
  #2  
Old 03-07-2004, 07:54 AM
*WyoWhisper*
 
Posts: n/a
Re: collapsed cases in a 7mmRUM?????

sometimes if you have and case lube or foreign substance on the case it will do this... I have had too much case lube on a case already and it has "dimpled" the case..
Reply With Quote
  #3  
Old 03-07-2004, 08:28 AM
Gold Member
 
Join Date: Sep 2002
Location: Illinois
Posts: 836
Re: collapsed cases in a 7mmRUM?????

I have the same rifle in the same cal. and the same problem when I first began loading for it. The problem is the bullet is exiting the neck before the pressure builds enough to seal the neck. Gasses are passing buy the neck and indenting the case. The solution is to seat the bullet deeper into the case to give more time to build the kind of pressure needed to expand the case enough to seal. You should also be using a mag. primer with this case if you're not already doing this. Let us know if this fixes the problem. There are a couple of other things you can do too, like increasing the neck tension.
db

[ 03-07-2004: Message edited by: dbhostler ]
Reply With Quote
  #4  
Old 03-07-2004, 11:09 PM
Silver Member
 
Join Date: Sep 2002
Posts: 453
Re: collapsed cases in a 7mmRUM?????

We are using an RCBS FL die set and retumbo with 162gr a-max pills. I am thinking you are on to the same conclusion I am (not enough pressure build in enough time) I will see what we can do to increase the neck tension.

Ric,...I made sure he patched the kroil from the tube and mopped the bore,....but I will check on the case lube idea as he may have left some on the brass.

Thanks guys.
__________________
You try to get closer to the target,..and I keep trying to get further away.
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes


Similar Threads for: collapsed cases in a 7mmRUM?????
Thread Thread Starter Forum Replies Last Post
7mmrum 162 a-max Rifles, Bullets, Barrels and Ballistics 5 09-04-2012 10:48 AM
New cases verses Fire formed cases Topshot Reloading 4 11-02-2009 08:46 AM
Getting rid of the 7mmRUM + .22 bullets Hicks Reloading Equipment and Components 1 10-29-2009 10:21 PM
300 RUM to 7MMRUM?? 260shooter Reloading 2 06-23-2005 05:28 PM
Making 300 RUM cases out of Norma 404 Jeffery cases? Kanab Reloading 11 03-31-2005 10:32 AM


All times are GMT -5. The time now is 06:56 AM.


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