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Rifles, Reloading, Optics, Equipment
Reloading
Neck sizing with FL dies
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<blockquote data-quote="Bart B" data-source="post: 688671" data-attributes="member: 5302"><p>Most folks remove the sizing button 'cause they know it too often bends case necks as it comes back up through the sized down case neck. But that means the fired case neck will be sized down several thousandths too much. </p><p></p><p>Seating bullets in that small of a case neck will typically scrape off a lot of jacket material. And it won't be exactly the same amount all the way around. So the otherwise well balanced bullet now is very much unbalanced. Do you want to shoot unbalanced bullets that jump off the bore axis as they leave the muzzle? And the peak pressure will be much higher for a given load with a bullet held extra tight by the case mouth. To say nothing of the often-bent case necks from doing this.</p><p></p><p>If the full length sizing die's neck is lapped out to a couple thousandths smaller than a loaded round's neck diameter, then it's the same thing as a full bushing die with its bushing diameter the same diameter as a lapped out standard die's neck. For example, if the neck diameter on a loaded round is .308", the sizing die's neck diameter (either the bushing or die neck) should be .306". That'll let the case neck spring back about .001" for enough neck tension to hold the bullet securely. For heavy recoiling rifles and heavy bullets for a given caliber, sometimes that die neck diameter needs to be .003" smaller.</p><p></p><p>One other thing, Redding makes shell holders that come in a set with .002" height differences. When a full length sizing die's locked in the press such that fired case shoulders are set back .002", the bottom of the die often is a couple thousandths above the shell holder. Using a shell holder of the correct height to stop against will keep your full length sized case headspace (head to shoulder length) to more consistant dimensions. It more or less eliminates the spread in this dimension caused by uneven amounts of case lube on the case that's often happens when spraying or rolling on case lube. Just use the shell holder that lets your fired case shoulder get set back no more than .003".</p></blockquote><p></p>
[QUOTE="Bart B, post: 688671, member: 5302"] Most folks remove the sizing button 'cause they know it too often bends case necks as it comes back up through the sized down case neck. But that means the fired case neck will be sized down several thousandths too much. Seating bullets in that small of a case neck will typically scrape off a lot of jacket material. And it won't be exactly the same amount all the way around. So the otherwise well balanced bullet now is very much unbalanced. Do you want to shoot unbalanced bullets that jump off the bore axis as they leave the muzzle? And the peak pressure will be much higher for a given load with a bullet held extra tight by the case mouth. To say nothing of the often-bent case necks from doing this. If the full length sizing die's neck is lapped out to a couple thousandths smaller than a loaded round's neck diameter, then it's the same thing as a full bushing die with its bushing diameter the same diameter as a lapped out standard die's neck. For example, if the neck diameter on a loaded round is .308", the sizing die's neck diameter (either the bushing or die neck) should be .306". That'll let the case neck spring back about .001" for enough neck tension to hold the bullet securely. For heavy recoiling rifles and heavy bullets for a given caliber, sometimes that die neck diameter needs to be .003" smaller. One other thing, Redding makes shell holders that come in a set with .002" height differences. When a full length sizing die's locked in the press such that fired case shoulders are set back .002", the bottom of the die often is a couple thousandths above the shell holder. Using a shell holder of the correct height to stop against will keep your full length sized case headspace (head to shoulder length) to more consistant dimensions. It more or less eliminates the spread in this dimension caused by uneven amounts of case lube on the case that's often happens when spraying or rolling on case lube. Just use the shell holder that lets your fired case shoulder get set back no more than .003". [/QUOTE]
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Neck sizing with FL dies
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