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Rifles, Reloading, Optics, Equipment
Reloading
Headspace and case stretch
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<blockquote data-quote="bigedp51" data-source="post: 1634337" data-attributes="member: 28965"><p>You can't judge case shoulder location on new rimmed and belted cases.</p><p></p><p>Below is a new unfired .303 British case in a Wilson case gauge. And the case would drop further into the gauge but the rim is stopping it from moving further. The Enfield rifle this case will be fired in will not close on a NO-GO gauge but still has .009 head gap clearance due to the case rim thickness.</p><p></p><p><img src="https://i.imgur.com/RBeuevm.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p><p></p><p></p><p>Below the case belt manufacturing headspace can vary .008 and the chamber headspace can vary .007. And the NO-GO gauge is .224 so you can see the case belt will make the biggest difference in head clearance. </p><p></p><p><img src="https://i.imgur.com/O3zQ5WP.png" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p><p></p><p>You can take a new unfired case and measure from the case mouth to the base of the case. And then take a fired spent primer and start the primer into the primer pocket with just your fingers.</p><p></p><p><img src="https://i.imgur.com/oNIvIiX.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p><p></p><p><img src="https://i.imgur.com/zQxlYGp.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p><p></p><p>Now chamber the case and let the bolt face seat the primer and extract the case. Then measure the case from the case mouth to the base of the primer and subtract the first case measurement from the second. And this will be your head clearance or air space between the rear of the case and the bolt face. And this will be how far the case will have to stretch on the first firing to contact the bolt face. Meaning the case shoulder location means nothing until the case is fired. And what is important is your head clearance with new cases and not the shoulder location.</p><p></p><p><img src="https://i.imgur.com/HK76WCp.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p></blockquote><p></p>
[QUOTE="bigedp51, post: 1634337, member: 28965"] You can't judge case shoulder location on new rimmed and belted cases. Below is a new unfired .303 British case in a Wilson case gauge. And the case would drop further into the gauge but the rim is stopping it from moving further. The Enfield rifle this case will be fired in will not close on a NO-GO gauge but still has .009 head gap clearance due to the case rim thickness. [IMG]https://i.imgur.com/RBeuevm.jpg[/IMG] Below the case belt manufacturing headspace can vary .008 and the chamber headspace can vary .007. And the NO-GO gauge is .224 so you can see the case belt will make the biggest difference in head clearance. [img]https://i.imgur.com/O3zQ5WP.png[/img] You can take a new unfired case and measure from the case mouth to the base of the case. And then take a fired spent primer and start the primer into the primer pocket with just your fingers. [img]https://i.imgur.com/oNIvIiX.jpg[/img] [img]https://i.imgur.com/zQxlYGp.jpg[/img] Now chamber the case and let the bolt face seat the primer and extract the case. Then measure the case from the case mouth to the base of the primer and subtract the first case measurement from the second. And this will be your head clearance or air space between the rear of the case and the bolt face. And this will be how far the case will have to stretch on the first firing to contact the bolt face. Meaning the case shoulder location means nothing until the case is fired. And what is important is your head clearance with new cases and not the shoulder location. [img]https://i.imgur.com/HK76WCp.jpg[/img] [/QUOTE]
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Reloading
Headspace and case stretch
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