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Rifles, Reloading, Optics, Equipment
Reloading
Shoulder bump FL sizing and measurements
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<blockquote data-quote="Tac-O" data-source="post: 1786943" data-attributes="member: 109994"><p>So I did some extra measurements yesterday eveninga here is what I found:</p><p></p><p>4x fired unsized federal and Winchester cases were 2.040 or 2.041 to the shoulder. Chambering these cases still didn't seem to give hardly any more resistance closing the bolt. I put a single piece of scotch tape (0.002 thick) on the base of one of these cases, colored the shoulders with a sharpie, and chambered it, which gave a stiff closing and opening of the bolt and showed rub marks on the shoulder. I then used the method of finding headspace that was in the link in this thread, where you start a spent primer by hand into a fired unsized case and then chamber it, allowing the bolt to push the primer in when the case shoulder hits the end of the chamber. So, measuring this case to the shoulder with the primer pushed in by the bolt gave me 2.043.</p><p></p><p>My 1x fired win cases that I mentioned in my original post measure 2.038 to shoulder. Given that I've only been shooting 150gr jacketed bullets with 57gr h4350, I guess I'm not surprised that even my 4x fired cases still aren't at 2.043. I also found some information that states shooting reduced loads can cause a decrease in headspace length of the fired case due to the firing pin slamming the case into the chamber shoulder and there not being enough pressure to stretch the brass back to the bolt.</p><p></p><p>I think I've got it figured out!</p><p>Except, now I feel like I'm not sure how to correctly set my FL sizing die :/</p></blockquote><p></p>
[QUOTE="Tac-O, post: 1786943, member: 109994"] So I did some extra measurements yesterday eveninga here is what I found: 4x fired unsized federal and Winchester cases were 2.040 or 2.041 to the shoulder. Chambering these cases still didn't seem to give hardly any more resistance closing the bolt. I put a single piece of scotch tape (0.002 thick) on the base of one of these cases, colored the shoulders with a sharpie, and chambered it, which gave a stiff closing and opening of the bolt and showed rub marks on the shoulder. I then used the method of finding headspace that was in the link in this thread, where you start a spent primer by hand into a fired unsized case and then chamber it, allowing the bolt to push the primer in when the case shoulder hits the end of the chamber. So, measuring this case to the shoulder with the primer pushed in by the bolt gave me 2.043. My 1x fired win cases that I mentioned in my original post measure 2.038 to shoulder. Given that I've only been shooting 150gr jacketed bullets with 57gr h4350, I guess I'm not surprised that even my 4x fired cases still aren't at 2.043. I also found some information that states shooting reduced loads can cause a decrease in headspace length of the fired case due to the firing pin slamming the case into the chamber shoulder and there not being enough pressure to stretch the brass back to the bolt. I think I've got it figured out! Except, now I feel like I'm not sure how to correctly set my FL sizing die :/ [/QUOTE]
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Rifles, Reloading, Optics, Equipment
Reloading
Shoulder bump FL sizing and measurements
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