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Rifles, Reloading, Optics, Equipment
Reloading
CBTO question
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<blockquote data-quote="entoptics" data-source="post: 1735693" data-attributes="member: 104268"><p>Technically, the distance from the bolt face to the 0.300 (lands diameter) is going to be the same in any given rifle. The difference is, the bullet "ogive" is somewhere just before 0.300. So what you're measuring isn't exactly the distance from the bolt face to the bore.</p><p></p><p>For example, my Hornady comparators are 0.001-0.002" under bore diameter. So for a shallow sloped ogive, the distance between 0.300 and 0.299 is further than one with a steep ogive angle.</p><p></p><p>Also, since you're not actually trying to measure bolt face to bore diameter distance, but instead, where the bullet actually starts touching something in the throat, the throat dimensions and lead angle will affect where the bullet actually starts to touch, which isn't necessarily the bore diameter.</p><p></p><p>The difference is likely to be minimal (a few thousandths) with similar bullet designs, but as an extreme example, imagine a wadcutter bullet and an extreme VLD. The wadcutter would hit the throat at the 0.308 bullet diameter, and the VLD would hit the throat at the 0.300 lands diameter somewhere much further into the chamber.</p></blockquote><p></p>
[QUOTE="entoptics, post: 1735693, member: 104268"] Technically, the distance from the bolt face to the 0.300 (lands diameter) is going to be the same in any given rifle. The difference is, the bullet "ogive" is somewhere just before 0.300. So what you're measuring isn't exactly the distance from the bolt face to the bore. For example, my Hornady comparators are 0.001-0.002" under bore diameter. So for a shallow sloped ogive, the distance between 0.300 and 0.299 is further than one with a steep ogive angle. Also, since you're not actually trying to measure bolt face to bore diameter distance, but instead, where the bullet actually starts touching something in the throat, the throat dimensions and lead angle will affect where the bullet actually starts to touch, which isn't necessarily the bore diameter. The difference is likely to be minimal (a few thousandths) with similar bullet designs, but as an extreme example, imagine a wadcutter bullet and an extreme VLD. The wadcutter would hit the throat at the 0.308 bullet diameter, and the VLD would hit the throat at the 0.300 lands diameter somewhere much further into the chamber. [/QUOTE]
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Reloading
CBTO question
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