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Fixing ejector marks on headstamp
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<blockquote data-quote="Rich Coyle" data-source="post: 2788054" data-attributes="member: 70559"><p>I did an accuracy test with squared heads compared to factory head brass. Following are the results.</p><p></p><p><strong> SQUARED HEADS</strong></p><p>Rich Coyle (541) 479-4646</p><p>May, 1997</p><p></p><p>Theory: Cases with squared heads will print better groups than standard cases when everything else is equal.</p><p>A Savage .223 with a 26" blue barrel in a non-pillar bedded polymer stock was used to verify the theory. The only modification being a trigger job to reduce the intolerable eight-pound pull to a more pleasant two pounds.</p><p>I used moly-coated 52-grain JLK low-drag benchrest bullets; energized by 28.5 grains of AA2230. For a little variety, both Remington 7½ Benchrest and CCI 400 standard small rifle primers sparked their respective loads. I started with 100 Remington cases, which had been fired seven times. I prepared them for this test by first full-length resizing them because the bolt was a little stiff on the closing cycle. After trimming them to length, chamfering, deburing the flash holes inside and squaring the primer pockets, I weighed them. Forty fell within my tolerance of .1 grain. Using a Wilson case trimmer, I squared half the cases. While some needed no squaring, I found the worst cases needed to be trimmed .002" to bring them into square. They were then fire-formed and neck-sized.</p><p></p><p>Five shots at 100 yards established the groups. I fired two groups primed with the Remington 7½ Benchrest primers first. Following these, I fired four groups with the CCI 400 standard primers. The last two groups used the remaining Remington primed loads. I used this system so fouling (or lack of same) would not favor either company's primers.</p><p>The first Remington primed factory cases punched an .843" group. The squared Remington primed cases made a group of .513". The CCI primed factory base is slightly better than the bench rest primed group at .800". The squared CCI primed cases' group came in with a phenomenal .396". Following with the next CCI factory base, I fired a .909" group. The CCI primed cases' groups are certainly surprising. The next one is .469". The second Remington primed factory case is better than the first one at .606". The Remington primed square case is .685".</p><p>The averages are:</p><p>Remington primed factory cases: .7245"</p><p>Remington primed squared cases: .5990"</p><p> </p><p>CCI primed factory bases averaged: .8545"</p><p>CCI primed squared cases averaged: .4325"</p><p></p><p>A week later I shot another eight groups to verify the first findings. The first Remington primed factory cases produce an .800" group. The square base Remington primed group is supporting the theory with a smaller at .757". The first CCI primed factory case group comes in at .556". Since smaller is better, the square base CCI primers triumph with a .500" group. The next CCI primed factory case load punched a .539" group. This is followed by the CCI primed square cases producing a sorry .683" group. The last Remington primed factory cases produced holes that spread .668". The last Remington primed square base group follows theory by printing .599".</p><p>This gives us four groups with each type of case for comparison. The averages of the last four groups are:</p><p>Remington primed factory case is .7293"</p><p>Remington primed square base is .6385"</p><p>CCI primed factory is .7010"</p><p>CCI primed square is .5120" </p><p></p><p>These numbers favor the Remington primed square bases by more than an 1/8", and the CCI primed cases by more than 3/16".</p><p></p><p>The importance of a "little variety" mentioned above obviously proves the value of trying different primers in one's quest for maximum accuracy.</p><p></p><p>Results: The averages of the group's tend to support the theory stated</p></blockquote><p></p>
[QUOTE="Rich Coyle, post: 2788054, member: 70559"] I did an accuracy test with squared heads compared to factory head brass. Following are the results. [B] SQUARED HEADS[/B] Rich Coyle (541) 479-4646 May, 1997 Theory: Cases with squared heads will print better groups than standard cases when everything else is equal. A Savage .223 with a 26" blue barrel in a non-pillar bedded polymer stock was used to verify the theory. The only modification being a trigger job to reduce the intolerable eight-pound pull to a more pleasant two pounds. I used moly-coated 52-grain JLK low-drag benchrest bullets; energized by 28.5 grains of AA2230. For a little variety, both Remington 7½ Benchrest and CCI 400 standard small rifle primers sparked their respective loads. I started with 100 Remington cases, which had been fired seven times. I prepared them for this test by first full-length resizing them because the bolt was a little stiff on the closing cycle. After trimming them to length, chamfering, deburing the flash holes inside and squaring the primer pockets, I weighed them. Forty fell within my tolerance of .1 grain. Using a Wilson case trimmer, I squared half the cases. While some needed no squaring, I found the worst cases needed to be trimmed .002" to bring them into square. They were then fire-formed and neck-sized. Five shots at 100 yards established the groups. I fired two groups primed with the Remington 7½ Benchrest primers first. Following these, I fired four groups with the CCI 400 standard primers. The last two groups used the remaining Remington primed loads. I used this system so fouling (or lack of same) would not favor either company's primers. The first Remington primed factory cases punched an .843" group. The squared Remington primed cases made a group of .513". The CCI primed factory base is slightly better than the bench rest primed group at .800". The squared CCI primed cases' group came in with a phenomenal .396". Following with the next CCI factory base, I fired a .909" group. The CCI primed cases' groups are certainly surprising. The next one is .469". The second Remington primed factory case is better than the first one at .606". The Remington primed square case is .685". The averages are: Remington primed factory cases: .7245" Remington primed squared cases: .5990" CCI primed factory bases averaged: .8545" CCI primed squared cases averaged: .4325" A week later I shot another eight groups to verify the first findings. The first Remington primed factory cases produce an .800" group. The square base Remington primed group is supporting the theory with a smaller at .757". The first CCI primed factory case group comes in at .556". Since smaller is better, the square base CCI primers triumph with a .500" group. The next CCI primed factory case load punched a .539" group. This is followed by the CCI primed square cases producing a sorry .683" group. The last Remington primed factory cases produced holes that spread .668". The last Remington primed square base group follows theory by printing .599". This gives us four groups with each type of case for comparison. The averages of the last four groups are: Remington primed factory case is .7293" Remington primed square base is .6385" CCI primed factory is .7010" CCI primed square is .5120" These numbers favor the Remington primed square bases by more than an 1/8", and the CCI primed cases by more than 3/16". The importance of a "little variety" mentioned above obviously proves the value of trying different primers in one's quest for maximum accuracy. Results: The averages of the group's tend to support the theory stated [/QUOTE]
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