Long Range Hunting Online Magazine


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

Reloading Techniques For Reloading


Reply

7RUM case denting when firing (pic)

 
LinkBack Thread Tools Display Modes
  #8  
Old 11-08-2008, 09:21 PM
Platinum Member
 
Join Date: Feb 2004
Location: Pennsyltucky
Posts: 2,625
Re: 7RUM case denting when firing (pic)

as 6mm said, when you put a loaded round in the chamber, there should be clearance between the case and chamber in the neck area. .002 is also what i would consider minimum. you've stated a loaded round and fired measure the same in the neck. that's saying there's very little, if any clearance between the 2. potentially a very dangerous situation.

as for the other bullets not having the same consequences, every bullet is different and the others probably make more pressure due to baring surface length, material hardness or several other things. i still think you're too low with pressure. that's what causes denting like you have. you might try chronographing the speeds. most of the time this will tell you if you're in the ballpark or not. but first i'd make sure you have proper clearance in the neck area.
Reply With Quote
  #9  
Old 11-08-2008, 09:38 PM
Gold Member
 
Join Date: Sep 2002
Location: Illinois
Posts: 836
Re: 7RUM case denting when firing (pic)

Brain, you are correct in your assumption. I had a Rem 7 UM do the same thing some time ago. You can do several things, use more powder, seat the bullet deeper in the case, increase neck tension or use a hotter primer. By the looks of your load, I would begin by seating the bullet deeper and increase neck tension.
db
Reply With Quote
  #10  
Old 11-08-2008, 10:06 PM
Silver Member
 
Join Date: Jan 2007
Location: VA
Posts: 150
Re: 7RUM case denting when firing (pic)

Thanks for all the input. It's very much appreciated.


In this particular circumstance, yes, the fired case neck diameter was .001 less than loaded round diameter. This is not due to a tight neck chamber, but because the case did not expand. Chamber diameter in the neck area is 0.322 which gives me 0.008 of clearance with a loaded round.

Unless I'm hunting, or shooting a match, everything gets shot over a chronograph and recorded. 94gr = 3330, 3322; up to 98gr = 3372, 3379. I believe these to be acceptable velocities for a 26" barrel and in line comparatively with other loads I have used in this rifle.

I too think pressure is too low. Before I try a different powder I am going to seat the VLD's deeper into the case for more bearing surface engagement. With the 168 VLD's there is only 0.073 of bearing surface making contact with the neck. The 162 SST's have the entire length of the neck (0.287) contacting the bearing surface. This should allow for more dwell time and resulting pressure increase for the case to expand before the mouth of the case is void.

I'll post results when I get them.

Thanks again.
Reply With Quote
  #11  
Old 11-08-2008, 10:49 PM
Gold Member
 
Join Date: Sep 2002
Location: Illinois
Posts: 836
Re: 7RUM case denting when firing (pic)

FYI this subject has been discussed several times before. It's been a few years ago, if I remember right, I brought it up when I began loading for my new 7UM Sendero. If you have a mind to, you can dig far enough and read the posts.
db
Reply With Quote
  #12  
Old 11-09-2008, 09:36 AM
Bronze Member
 
Join Date: Jul 2007
Posts: 62
Re: 7RUM case denting when firing (pic)

Try some H-1000 or IMR 7828 and see if it still happens.
Reply With Quote
  #13  
Old 11-09-2008, 02:32 PM
Platinum Member
 
Join Date: Apr 2005
Location: Alaska
Posts: 3,439
Re: 7RUM case denting when firing (pic)

Quote:
Originally Posted by dbhostler View Post
FYI this subject has been discussed several times before. It's been a few years ago, if I remember right, I brought it up when I began loading for my new 7UM Sendero. If you have a mind to, you can dig far enough and read the posts.
db
Is it possible to search back more than one year? If so, how? I see a max of one year when I perform searches. Anybody know?
Reply With Quote
  #14  
Old 11-09-2008, 04:52 PM
KRP KRP is offline
Gold Member
 
Join Date: Dec 2007
Location: Kuna, ID
Posts: 594
Re: 7RUM case denting when firing (pic)

Go to the advanced search and under "Find Posts from" put in "A Year Ago and older". Using "Any date" will work also but you are limited to 500 results so you may need to narrow the search and/or specifically search the older than 1 year posts.

Last edited by KRP; 11-09-2008 at 04:57 PM.
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes


Similar Threads for: 7RUM case denting when firing (pic)
Thread Thread Starter Forum Replies Last Post
7RUM Sendero TeamKiess Gun Parts - Stocks, Barrels, Actions, etc. 1 06-03-2011 06:28 PM
7RUM 1/12 help Limbic Reloading 3 08-09-2010 08:58 AM
Federal 210 primers denting ? tim227 Reloading 4 12-11-2009 11:25 PM
175smk in a 7RUM Booney Reloading 6 10-09-2009 07:10 PM
Best load for 7RUM DCGS Reloading 10 01-06-2008 12:07 AM


All times are GMT -5. The time now is 10:28 PM.


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