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Rifles, Reloading, Optics, Equipment
Reloading
Measuring Base to Ogive Length w/ Hornady OAL Gauge
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<blockquote data-quote="Bart B" data-source="post: 814377" data-attributes="member: 5302"><p>Woods, those FL dies all had a gap between their bottom and the shell holder when their shoulder was snug against the headspace gauge's shoulder; different amounts for each one. It was the spring of the press that let them move up when sizing cases so the shoulder was pushed forward. The term "press headspace" was given to me by an RCBS rep back in the 1960's referring to the distance between the shell holder bottom and die shoulder. It has a static number when the ram's at the top of its stroke without a case and a dynamic number when a lubed case is in the press. The difference between them is the amount of spring the press frame has.</p><p></p><p>If all those .308 FL dies were set so the shell holder stopped against them with the ram at the top of its stroke, all of them would push the fired case shoulder back a few thousandths and case headspace would be close to SAAMI minimum. Head clearance on the cases would be too much for best accuracy and case life. I prefer sized case headspace to be no more than 2 thousandths less than fired case headspace. So I set all my FL dies to have a few thousandths clearance to the shell holder when the press is in a dynamic condition with a lubed case in it.</p><p></p><p>To keep FL sized case headspace at the same amount after sizing, all those dies need a few thousandths clearance to the shell holder. Each one has a different dimension from the die bottom to the shoulder reference; they're just like chambers in barrels. If the shell holder bottom distance to the die shoulder could be measured, it has to be less than the desired case headspace in a static condition of the press if case headspace after sizing needs to equal or be less than fired case headspace due to the spring of the press. Same thing with my FL dies for several rimless bottleneck cartridges. This is why I mentioned the Redding competition shell holders with different heights above the standard .125" so dies could contact them and set fired case shoulders back as desired or even not at all.</p><p></p><p>Have you measured case headspace on fired rimless bottleneck cases before and after FL sizing with the shell holder stopping against the die's bottom? All of my FL dies set the shoulders back a few to several thousandths.</p><p></p><p>I tumble a few dozen decapped and cleaned cases in a foam lined tumbler with a few drops of case lube sprinkled on the foam. That uniformly lubes all the case exterior areas so the friction each has in the die is uniform and sized case headspace has a 1 to 2 thousandths spread across a batch of cases. I tried lubing only the case body decades ago, but got more consistant sized case headspace lubing cases' body, shoulder and neck. </p><p></p><p>You don't need to "shout" at me using all capital letters in your comments. It's a lot easier for everyone to read lower case letters in sentences.</p></blockquote><p></p>
[QUOTE="Bart B, post: 814377, member: 5302"] Woods, those FL dies all had a gap between their bottom and the shell holder when their shoulder was snug against the headspace gauge's shoulder; different amounts for each one. It was the spring of the press that let them move up when sizing cases so the shoulder was pushed forward. The term "press headspace" was given to me by an RCBS rep back in the 1960's referring to the distance between the shell holder bottom and die shoulder. It has a static number when the ram's at the top of its stroke without a case and a dynamic number when a lubed case is in the press. The difference between them is the amount of spring the press frame has. If all those .308 FL dies were set so the shell holder stopped against them with the ram at the top of its stroke, all of them would push the fired case shoulder back a few thousandths and case headspace would be close to SAAMI minimum. Head clearance on the cases would be too much for best accuracy and case life. I prefer sized case headspace to be no more than 2 thousandths less than fired case headspace. So I set all my FL dies to have a few thousandths clearance to the shell holder when the press is in a dynamic condition with a lubed case in it. To keep FL sized case headspace at the same amount after sizing, all those dies need a few thousandths clearance to the shell holder. Each one has a different dimension from the die bottom to the shoulder reference; they're just like chambers in barrels. If the shell holder bottom distance to the die shoulder could be measured, it has to be less than the desired case headspace in a static condition of the press if case headspace after sizing needs to equal or be less than fired case headspace due to the spring of the press. Same thing with my FL dies for several rimless bottleneck cartridges. This is why I mentioned the Redding competition shell holders with different heights above the standard .125" so dies could contact them and set fired case shoulders back as desired or even not at all. Have you measured case headspace on fired rimless bottleneck cases before and after FL sizing with the shell holder stopping against the die's bottom? All of my FL dies set the shoulders back a few to several thousandths. I tumble a few dozen decapped and cleaned cases in a foam lined tumbler with a few drops of case lube sprinkled on the foam. That uniformly lubes all the case exterior areas so the friction each has in the die is uniform and sized case headspace has a 1 to 2 thousandths spread across a batch of cases. I tried lubing only the case body decades ago, but got more consistant sized case headspace lubing cases' body, shoulder and neck. You don't need to "shout" at me using all capital letters in your comments. It's a lot easier for everyone to read lower case letters in sentences. [/QUOTE]
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Measuring Base to Ogive Length w/ Hornady OAL Gauge
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