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Rifles, Reloading, Optics, Equipment
Reloading
Wondering when to retire .30-06 brass (sectioned brass photos included)
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<blockquote data-quote="bigedp51" data-source="post: 1389145" data-attributes="member: 28965"><p>Your shoulder bump is the equivalent of your head clearance when the cartridge is chambered. And the head clearance is the distance the rear of the case stretches to meet the bolt face. The thumb rule of .001 to .002 shoulder bump is well within the elastic limits of the brass and not have any stretching and thinning of the brass.</p><p></p><p><img src="https://i.imgur.com/HK76WCp.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p><p></p><p>The .308 cases below were fired in a brand new Savage bolt action and the full length die was setup to make hard contact with the shell holder. The rifles headspace was not given nor the amount of shoulder bump. Meaning the actual shoulder bump and head clearance was unknown, so the case life listed is ball park. And if the shoulder bump had been held to .001 to .002 these cases would have lasted longer.</p><p></p><p><img src="https://i.imgur.com/TDwPD1Q.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p><p></p><p><img src="https://i.imgur.com/XEuny9C.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p><p></p><p>As you can see above the quality, hardness and thickness of the case in its base has a lot to do with case life. Example military .308/7.62 cases are made of harder brass and are thicker in the base and will last longer than thinner commercial brands of brass.</p><p></p><p>Bottom line, the cases in your photo look good, and I have cases over 25 years old that I lost count of how many times they have been fired. These were never annealed and fail with cracked necks with no sign of case head separations.</p><p></p><p>I use a $100.00 bent paper clip below, a RCBS Case mastering gauge that will show case thinning in .001 of an inch. This gauge is the Swiss Army Knife of gauges and also checks runout, neck thickness and other functions. In the photo below is a sectioned factory loaded Winchester .303 British case that stretched and thinned .009 on its first firing. And the rifles headspace was set below the NO-GO gauge, but the thin Winchester case had thin rims that added to its head clearance.</p><p></p><p><img src="https://i.imgur.com/jDCS39v.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p><p></p><p><img src="https://i.imgur.com/YoV80b4.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p><p></p><p><img src="https://i.imgur.com/sHgqVJR.gif" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p><p></p><p>Your resizing die should be setup to bump the case shoulder .001 to .002 below the red dotted line below. And the closer the shoulder is bumped to the green dotted line the more the case will stretch and thin.</p><p></p><p><img src="https://i.imgur.com/wm05ArY.gif" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p></blockquote><p></p>
[QUOTE="bigedp51, post: 1389145, member: 28965"] Your shoulder bump is the equivalent of your head clearance when the cartridge is chambered. And the head clearance is the distance the rear of the case stretches to meet the bolt face. The thumb rule of .001 to .002 shoulder bump is well within the elastic limits of the brass and not have any stretching and thinning of the brass. [IMG]https://i.imgur.com/HK76WCp.jpg[/IMG] The .308 cases below were fired in a brand new Savage bolt action and the full length die was setup to make hard contact with the shell holder. The rifles headspace was not given nor the amount of shoulder bump. Meaning the actual shoulder bump and head clearance was unknown, so the case life listed is ball park. And if the shoulder bump had been held to .001 to .002 these cases would have lasted longer. [IMG]https://i.imgur.com/TDwPD1Q.jpg[/IMG] [IMG]https://i.imgur.com/XEuny9C.jpg[/IMG] As you can see above the quality, hardness and thickness of the case in its base has a lot to do with case life. Example military .308/7.62 cases are made of harder brass and are thicker in the base and will last longer than thinner commercial brands of brass. Bottom line, the cases in your photo look good, and I have cases over 25 years old that I lost count of how many times they have been fired. These were never annealed and fail with cracked necks with no sign of case head separations. I use a $100.00 bent paper clip below, a RCBS Case mastering gauge that will show case thinning in .001 of an inch. This gauge is the Swiss Army Knife of gauges and also checks runout, neck thickness and other functions. In the photo below is a sectioned factory loaded Winchester .303 British case that stretched and thinned .009 on its first firing. And the rifles headspace was set below the NO-GO gauge, but the thin Winchester case had thin rims that added to its head clearance. [IMG]https://i.imgur.com/jDCS39v.jpg[/IMG] [IMG]https://i.imgur.com/YoV80b4.jpg[/IMG] [IMG]https://i.imgur.com/sHgqVJR.gif[/IMG] Your resizing die should be setup to bump the case shoulder .001 to .002 below the red dotted line below. And the closer the shoulder is bumped to the green dotted line the more the case will stretch and thin. [img]https://i.imgur.com/wm05ArY.gif[/img] [/QUOTE]
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Reloading
Wondering when to retire .30-06 brass (sectioned brass photos included)
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