Case Rim Expansion - 6.5 Saum

G

gut_pile

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Recently I have began reloading with brass that has been fired one time. I am running into an issue where the rim of my brass is expanding and my brass will no longer go into my DBM and sometimes won't even go into the shell holder.

What could be causing this? I am not getting any extractor marks, and only very rarely will I get any type of bolt lift resistance (will have some after the gun gets hot but even then it's rare).

Also, is there a way to fix it?

Thanks
 
is this Norma brass? that is the only brass i have seen this problem with. what is actually happening is the extractor groove is collapsing and the dia. above the groove is expanding. i was getting this problem with their 7saum and 300rum.
 
What brass manufacturer? I would start measuring brass that has only been fired once and compare to second firing. Also look at SAAMI specs on rim diameter. Something is not right.
Especially if you can chamber rounds but won't fit your shell holder.
 
IMG_4018.jpeg

Brand new

IMG_4019.jpeg

Fired

IMG_4017.jpeg

Fired and resized
 
gut_pile said:
Hornady brass bought from GAP
Click to expand...
never used Hornady in the saum case so cant help with that but also never seen brass expand there. take a couple measurements on each case before and after and mark cases and try to get an average and not that your seeing differences in case lots being mixed together.
 
Here's the SAAMI spec for the SAUM family. Your measurement puts it real close to the middle of the tolerance which is good. If these are not fitting your reloading equipment but chamber in your rifle maybe the shell holder needs to be changed. .005 jump in size needs to be monitored as that does show growth.
Measure or monitor your primer pockets while your digging into this. If those are also going oversize you'll have to back off pressure or change brass if the Hornady are soft.
 

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If everything works in the rifle and no pressure signs, get another shell holder, could be a defect in the shell holder. Will unfired brass fit the mag without issues? You may have to work on the sides of the mag lips, smooth them or widen a bit. Maybe just open them up a little.
 

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