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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
30 Sherman Magnum 20” Build
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<blockquote data-quote="CA48" data-source="post: 2142310" data-attributes="member: 21446"><p>Running an 8 Twist.</p><p></p><p>I ran one case again, for 10 firings this time, but it could have gone more. </p><p>I didn't explain it very well last time but I was seeing increasing pressure with the same charge due to the piece of brass growing as I never trimmed it throughout out the process last time.</p><p></p><p>This time this I cleaned the barrel. Shot 1 factory Hornady round through it to help foul the barrel. I then grabbed a piece of adg that had been formed with a mild load and started. So 10 firings total counting the mild FF load. 1 at 83gr of N570 then 9 with 85.5gr.</p><p>No Pressure signs until the 4th firing then I started to get clickers and very faint ej marks that you really had to look for and could only find in the sunlight. With each shot I was lining up a letter on the case head with the ejector so I knew where to look. After the 6th firing I started pushing the shoulder back more. Then shots 7-10 the clickers went away but I was still getting the very faint ej shadows that you really had to look for in the sun to see.</p><p></p><p>As far as me pushing the shoulders back more and the clickers going away. Part of my thinking is when I took my initial shoulder measurements for my bump it was on a once fired case that was not fully formed yet in addition to the Hornady comparator which is not going to be perfect or in the exact right spot on the shoulder for a precise measurement. But the clickers did indeed go away once I started pushing shoulders back .001" more. I know this shouldn't have much to do with the base of the case not getting sized enough which is where clickers usually come from if I understand correctly, just relaying what I experienced. </p><p>After the case had been fired 10x i sized it again and measured the base with Mitutoyo calipers. It measured .5326"</p><p></p><p>The 10X fired case</p><p></p><p>[ATTACH=full]258650[/ATTACH]</p><p></p><p>The 9 velocity readings in order with 85.5gr of 570 at +.005" with the 215s after the barrel had been fouled with one shot. After looking at these readings it looks like I would have had a much lower ES if I had put a few more shots through the barrel before I started taking readings. It seemed to stabilize after the 3rd shot from clean bore.</p><p></p><p>1 Hornady factory </p><p>2 2966</p><p>3 2922</p><p>4 2956</p><p>5 2951</p><p>6 2946</p><p>7 2958</p><p>8 2956</p><p>9 2948</p><p>10 2955</p></blockquote><p></p>
[QUOTE="CA48, post: 2142310, member: 21446"] Running an 8 Twist. I ran one case again, for 10 firings this time, but it could have gone more. I didn’t explain it very well last time but I was seeing increasing pressure with the same charge due to the piece of brass growing as I never trimmed it throughout out the process last time. This time this I cleaned the barrel. Shot 1 factory Hornady round through it to help foul the barrel. I then grabbed a piece of adg that had been formed with a mild load and started. So 10 firings total counting the mild FF load. 1 at 83gr of N570 then 9 with 85.5gr. No Pressure signs until the 4th firing then I started to get clickers and very faint ej marks that you really had to look for and could only find in the sunlight. With each shot I was lining up a letter on the case head with the ejector so I knew where to look. After the 6th firing I started pushing the shoulder back more. Then shots 7-10 the clickers went away but I was still getting the very faint ej shadows that you really had to look for in the sun to see. As far as me pushing the shoulders back more and the clickers going away. Part of my thinking is when I took my initial shoulder measurements for my bump it was on a once fired case that was not fully formed yet in addition to the Hornady comparator which is not going to be perfect or in the exact right spot on the shoulder for a precise measurement. But the clickers did indeed go away once I started pushing shoulders back .001” more. I know this shouldn’t have much to do with the base of the case not getting sized enough which is where clickers usually come from if I understand correctly, just relaying what I experienced. After the case had been fired 10x i sized it again and measured the base with Mitutoyo calipers. It measured .5326” The 10X fired case [ATTACH type="full"]258650[/ATTACH] The 9 velocity readings in order with 85.5gr of 570 at +.005” with the 215s after the barrel had been fouled with one shot. After looking at these readings it looks like I would have had a much lower ES if I had put a few more shots through the barrel before I started taking readings. It seemed to stabilize after the 3rd shot from clean bore. 1 Hornady factory 2 2966 3 2922 4 2956 5 2951 6 2946 7 2958 8 2956 9 2948 10 2955 [/QUOTE]
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30 Sherman Magnum 20” Build
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