Scratching my head on this one

ZLBubba

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Minuteman
Jan 15, 2009
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I just pulled some brass out of my tumbler and started sorting the 40S&W brass to load a new batch. This will be the third time they've been loaded. I measured the whole batch before I shot them last time and I'm damn near positive the brass all measured between .840 and .850. Now, a significant portion of the brass is measuring about .835-7. I don't get it. Did my brass really lose length during the firing process? Should I throw all that brass away or just load the short brass?
 
Re: Scratching my head on this one

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ZLBubba</div><div class="ubbcode-body">I just pulled some brass out of my tumbler and started sorting the 40S&W brass to load a new batch. This will be the third time they've been loaded. I measured the whole batch before I shot them last time and I'm damn near positive the brass all measured between .840 and .850. Now, a significant portion of the brass is measuring about .835-7. I don't get it. Did my brass really lose length during the firing process? Should I throw all that brass away or just load the short brass? </div></div>
When you measured them before tumbling they had a slightly frayed edge from being sized , chamfered , tapered , crimped , fired . During tumbling that edge is pounded back down a bit and they measure shorter. After a few reloads a small amount of brass can be lost from the mouth of pistol cases more so than a rifle case. So as time goes on they can shorten a bit because low pressure pistol cases in general don't flow brass forward as much as rifle cases can.