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Rifles, Reloading, Optics, Equipment
Reloading
14 twist barrel and 68 gr .224 bullets
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<blockquote data-quote="Mikecr" data-source="post: 82255" data-attributes="member: 1521"><p>Thats right TBob.</p><p>Greenhill shows 10tw for the 69 Sierra, &gt;2800fps &amp; bullet measuring .898" long. But thats marginal really. With more precise software I get a 10tw Sg of ~1.27 @3500fps ICAO conditions. At 2500'ASL, and 75deg, Sg goes up to 1.43.</p><p>So 1:10 should work. But 1:9 is perfect - Sg @ ICAO = 1.56</p><p>If high enough in elevation, and really smoking it, 1:11 technically might work. But forget any twist slower for that bullet.</p></blockquote><p></p>
[QUOTE="Mikecr, post: 82255, member: 1521"] Thats right TBob. Greenhill shows 10tw for the 69 Sierra, >2800fps & bullet measuring .898" long. But thats marginal really. With more precise software I get a 10tw Sg of ~1.27 @3500fps ICAO conditions. At 2500'ASL, and 75deg, Sg goes up to 1.43. So 1:10 should work. But 1:9 is perfect - Sg @ ICAO = 1.56 If high enough in elevation, and really smoking it, 1:11 technically might work. But forget any twist slower for that bullet. [/QUOTE]
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Rifles, Reloading, Optics, Equipment
Reloading
14 twist barrel and 68 gr .224 bullets
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