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Hunting
Long Range Hunting & Shooting
7mm Rem mag 168gr or even 180Gr tumble and inaccuracy with 8 twist barrel?
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<blockquote data-quote="BallisticsGuy" data-source="post: 1624233" data-attributes="member: 96226"><p>As soon as someone says it'll be differently stable at longer ranges than at shorter ranges you can pretty much dismiss whatever comes before or after that. Bullets are either stable or unstable when they leave the muzzle. It's a boolean, yes or no. They will either tumble or they will not while in supersonic flight and they'll do it very early in the journey. Because the force trying to flip the bullet over is losing strength as the bullet slows down its velocity while the angular momentum that keeps it stable is relatively unchanged, hence the bullet only becomes more stable downrange. That's for pure supersonic flight only.</p><p></p><p>What will actually happen? It'll spin the lighter bullets just a bit harder than necessary and the lightest possible bullets it'll spin entirely too hard, all which can exacerbate any mass distribution inconsistencies in the bullet leading to potentially larger groups. Notice the "can" and "potentially" in that? It means that the practical consequences are likely to very much resemble "none at all". </p><p></p><p>You'll have what most .308 owners with 10 twist barrels have. A twist that's just fast enough for really heavy bullets, a bit excessive for mid-weight bulets and way too much light weight bullets. They're able to shoot just about anything they can stick in the case. Ask yourself, has everyone with a .308 burning 150gr pills on a 10 twist barrel had trouble? I've personally shot 500m matches with 110gr half-jacket .308 loads doing 3200 from a 10 twist barrel without issue. Sg on that is around 4. Ideal is around 1.5-ish. To get down to a 1.5 Sg on a 10 twisted .308 you need to start looking at >200gr bullets going REAL slow.</p><p></p><p>In really small bullets like .223 and under that are super light with very light jackets you can see bullets turn to grey puffs of smoke about 15 yards out from the barrel when they're spun exceedingly hard but they're also meant to be that fragile.</p></blockquote><p></p>
[QUOTE="BallisticsGuy, post: 1624233, member: 96226"] As soon as someone says it'll be differently stable at longer ranges than at shorter ranges you can pretty much dismiss whatever comes before or after that. Bullets are either stable or unstable when they leave the muzzle. It's a boolean, yes or no. They will either tumble or they will not while in supersonic flight and they'll do it very early in the journey. Because the force trying to flip the bullet over is losing strength as the bullet slows down its velocity while the angular momentum that keeps it stable is relatively unchanged, hence the bullet only becomes more stable downrange. That's for pure supersonic flight only. What will actually happen? It'll spin the lighter bullets just a bit harder than necessary and the lightest possible bullets it'll spin entirely too hard, all which can exacerbate any mass distribution inconsistencies in the bullet leading to potentially larger groups. Notice the "can" and "potentially" in that? It means that the practical consequences are likely to very much resemble "none at all". You'll have what most .308 owners with 10 twist barrels have. A twist that's just fast enough for really heavy bullets, a bit excessive for mid-weight bulets and way too much light weight bullets. They're able to shoot just about anything they can stick in the case. Ask yourself, has everyone with a .308 burning 150gr pills on a 10 twist barrel had trouble? I've personally shot 500m matches with 110gr half-jacket .308 loads doing 3200 from a 10 twist barrel without issue. Sg on that is around 4. Ideal is around 1.5-ish. To get down to a 1.5 Sg on a 10 twisted .308 you need to start looking at >200gr bullets going REAL slow. In really small bullets like .223 and under that are super light with very light jackets you can see bullets turn to grey puffs of smoke about 15 yards out from the barrel when they're spun exceedingly hard but they're also meant to be that fragile. [/QUOTE]
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7mm Rem mag 168gr or even 180Gr tumble and inaccuracy with 8 twist barrel?
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