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Joined: Dec 2008
Posts: 78,300
Campfire Oracle
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Campfire Oracle
Joined: Dec 2008
Posts: 78,300 |
George, Ive got a 1 in 12 twist that shoots 60 NBTs into little bugholes, even near sea level. Im using CFE223 and getting the same speed you are...
"...the left considers you vermin, and they'll kill you given the chance..." Bristoe
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Joined: Jul 2001
Posts: 60,086
Campfire Kahuna
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Campfire Kahuna
Joined: Jul 2001
Posts: 60,086 |
The 60-grain Ballistic Tip was designed to stabilize reasonably well in a 1-12 twist--which is why it isn't much longer than the 55, and probably why its BC is only slightly better than the 55's.
Nosler, like many bullet makers, often suggests rifling twists faster than required for certain bullets, to make damn sure they stabilize. Which is probably why they lump the 60 BT into theier "60-62 grain. fast twist" data for the .223.
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.” John Steinbeck
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Joined: Jan 2012
Posts: 252
Campfire Member
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OP
Campfire Member
Joined: Jan 2012
Posts: 252 |
No pet loads for 9-twist but for context mine is a 12-twist and shoots the 60-gr V-Max's quite well and I use H335 because I have a lot of it. My 60-gr loads thusly loaded get 3450 in a 23" tube-plenty for my 300-yd shots in the farm country I live in. These do not read out as max in my rifle.
Those should perform quite well.
"Are you going to pull those pistols or whistle Dixie?"
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Joined: Dec 2008
Posts: 78,300
Campfire Oracle
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Campfire Oracle
Joined: Dec 2008
Posts: 78,300 |
The 60-grain Ballistic Tip was designed to stabilize reasonably well in a 1-12 twist--which is why it isn't much longer than the 55, and probably why its BC is only slightly better than the 55's.
Nosler, like many bullet makers, often suggests rifling twists faster than required for certain bullets, to make damn sure they stabilize. Which is probably why they lump the 60 BT into theier "60-62 grain. fast twist" data for the .223. Figured as much when I ran the numbers through the Berger Twist Rate stability link you gave me...it works!
"...the left considers you vermin, and they'll kill you given the chance..." Bristoe
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Joined: Jul 2001
Posts: 60,086
Campfire Kahuna
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Campfire Kahuna
Joined: Jul 2001
Posts: 60,086 |
JBM Ballistics also has an on-line program based on the same formula, except for including a place to enter the length of plastic tips.
The guy who developed the formula Berger uses, Don Miller, eventually came to the conclusion that plastic tips are so light they don't affect stability much, so their length shouldn't be included when calculating stability. This is why the Berger formula suggests that 40-grain Hornady .204 V-Maxes won't even come close to stabilizing in the standard 1-12 twist, when anybody who's used them knows that's not so.
When using the Berger program with plastic-tipped bullets, I subtract 3/4 of the length of the tip from the bullet's overall length, which so far has worked pretty well--and comes close to the results from the JBM program.
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.” John Steinbeck
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